The Collaborative International Dictionary of English v.0.48:

Sign \Sign\, n. [F. signe, L. signum; cf. AS. segen, segn, a
   sign, standard, banner, also fr. L. signum. Cf. Ensign,
   Resign, Seal a stamp, Signal, Signet.]
   That by which anything is made known or represented; that
   which furnishes evidence; a mark; a token; an indication; a
   proof. Specifically:
   (a) A remarkable event, considered by the ancients as
       indicating the will of some deity; a prodigy; an omen.
   (b) An event considered by the Jews as indicating the divine
       will, or as manifesting an interposition of the divine
       power for some special end; a miracle; a wonder.
       [1913 Webster]

             Through mighty signs and wonders, by the power of
             the Spirit of God.                   --Rom. xv. 19.
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             It shall come to pass, if they will not believe
             thee, neither hearken to the voice of the first
             sign, that they will believe the voice of the
             latter sign.                         --Ex. iv. 8.
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   (c) Something serving to indicate the existence, or preserve
       the memory, of a thing; a token; a memorial; a monument.
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             What time the fire devoured two hundred and fifty
             men, and they became a sign.         --Num. xxvi.
                                                  10.
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   (d) Any symbol or emblem which prefigures, typifles, or
       represents, an idea; a type; hence, sometimes, a picture.
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             The holy symbols, or signs, are not barely
             significative; but what they represent is as
             certainly delivered to us as the symbols
             themselves.                          --Brerewood.
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             Saint George of Merry England, the sign of victory.
                                                  --Spenser.
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   (e) A word or a character regarded as the outward
       manifestation of thought; as, words are the sign of
       ideas.
   (f) A motion, an action, or a gesture by which a thought is
       expressed, or a command or a wish made known.
       [1913 Webster]

             They made signs to his father, how he would have
             him called.                          --Luke i. 62.
       [1913 Webster]
   (g) Hence, one of the gestures of pantomime, or of a language
       of a signs such as those used by the North American
       Indians, or those used by the deaf and dumb.
       [1913 Webster]

   Note: Educaters of the deaf distinguish between natural
         signs, which serve for communicating ideas, and
         methodical, or systematic, signs, adapted for the
         dictation, or the rendering, of written language, word
         by word; and thus the signs are to be distinguished
         from the manual alphabet, by which words are spelled on
         the fingers.
         [1913 Webster]
   (h) A military emblem carried on a banner or a standard.
       --Milton.
   (i) A lettered board, or other conspicuous notice, placed
       upon or before a building, room, shop, or office to
       advertise the business there transacted, or the name of
       the person or firm carrying it on; a publicly displayed
       token or notice.
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             The shops were, therefore, distinguished by painted
             signs, which gave a gay and grotesque aspect to the
             streets.                             --Macaulay.
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   (j) (Astron.) The twelfth part of the ecliptic or zodiac.
       [1913 Webster]

   Note: The signs are reckoned from the point of intersection
         of the ecliptic and equator at the vernal equinox, and
         are named, respectively, Aries ([Aries]), Taurus
         ([Taurus]), Gemini (II), Cancer ([Cancer]), Leo
         ([Leo]), Virgo ([Virgo]), Libra ([Libra]),
         Scorpio ([Scorpio]), Sagittarius ([Sagittarius]),
         Capricornus  ([Capricorn]), {Aquarius ([Aquarius]),
         Pisces ([Pisces]). These names were originally the
         names of the constellations occupying severally the
         divisions of the zodiac, by which they are still
         retained; but, in consequence of the procession of the
         equinoxes, the signs have, in process of time, become
         separated about 30 degrees from these constellations,
         and each of the latter now lies in the sign next in
         advance, or to the east of the one which bears its
         name, as the constellation Aries in the sign Taurus,
         etc.
         [1913 Webster]
   (k) (Alg.) A character indicating the relation of quantities,
       or an operation performed upon them; as, the sign +
       (plus); the sign -- (minus); the sign of division /, and
       the like.
   (l) (Med.) An objective evidence of disease; that is, one
       appreciable by some one other than the patient.
       [1913 Webster]

   Note: The terms symptom and and sign are often used
         synonymously; but they may be discriminated. A sign
         differs from a symptom in that the latter is perceived
         only by the patient himself. The term sign is often
         further restricted to the purely local evidences of
         disease afforded by direct examination of the organs
         involved, as distinguished from those evidence of
         general disturbance afforded by observation of the
         temperature, pulse, etc. In this sense it is often
         called physical sign.
         [1913 Webster]
   (m) (Mus.) Any character, as a flat, sharp, dot, etc.
   (n) (Theol.) That which, being external, stands for, or
       signifies, something internal or spiritual; -- a term
       used in the Church of England in speaking of an ordinance
       considered with reference to that which it represents.
       [1913 Webster]

             An outward and visible sign of an inward and
             spiritual grace.                     --Bk. of
                                                  Common Prayer.
       [1913 Webster]

   Note: See the Table of Arbitrary Signs, p. 1924.
         [1913 Webster]

   Sign manual.
   (a) (Eng. Law) The royal signature superscribed at the top of
       bills of grants and letter patent, which are then sealed
       with the privy signet or great seal, as the case may be,
       to complete their validity.
   (b) The signature of one's name in one's own handwriting.
       --Craig. Tomlins. Wharton.
       [1913 Webster]

   Syn: Token; mark; note; symptom; indication; signal; symbol;
        type; omen; prognostic; presage; manifestation. See
        Emblem.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sign \Sign\, v. i.
   1. To be a sign or omen. [Obs.] --Shak.
      [1913 Webster]

   2. To make a sign or signal; to communicate directions or
      intelligence by signs.
      [1913 Webster]

   3. Especially: To communicate in sign language.
      [PJC]

   4. To write one's name, esp. as a token of assent,
      responsibility, or obligation; as, he signed in red ink.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sign \Sign\, v. t. [imp. & p. p. Signed; p. pr. & vb. n.
   Signing.] [OE. seinen to bless, originally, to make the
   sign of the cross over; in this sense fr. ASS. segnian (from
   segn, n.), or OF. seignier, F. signer, to mark, to sign (in
   sense 3), fr. L. signare to mark, set a mark upon, from
   signum. See Sign, n.]
   1. To represent by a sign; to make known in a typical or
      emblematic manner, in distinction from speech; to signify.
      [1913 Webster]

            I signed to Browne to make his retreat. --Sir W.
                                                  Scott.
      [1913 Webster]

   2. To make a sign upon; to mark with a sign.
      [1913 Webster]

            We receive this child into the congregation of
            Christ's flock, and do sign him with the sign of the
            cross.                                --Bk. of Com
                                                  Prayer.
      [1913 Webster]

   3. To affix a signature to; to ratify by hand or seal; to
      subscribe in one's own handwriting.
      [1913 Webster]

            Inquire the Jew's house out, give him this deed,
            And let him sign it.                  --Shak.
      [1913 Webster]

   4. To assign or convey formally; -- used with away.
      [1913 Webster]

   5. To mark; to make distinguishable. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sign
    adj 1: used of the language of the deaf [syn: gestural,
           sign(a), signed, sign-language(a)]
    n 1: a perceptible indication of something not immediately
         apparent (as a visible clue that something has happened);
         "he showed signs of strain"; "they welcomed the signs of
         spring" [syn: sign, mark]
    2: a public display of a message; "he posted signs in all the
       shop windows"
    3: any nonverbal action or gesture that encodes a message;
       "signals from the boat suddenly stopped" [syn: signal,
       signaling, sign]
    4: structure displaying a board on which advertisements can be
       posted; "the highway was lined with signboards" [syn:
       signboard, sign]
    5: (astrology) one of 12 equal areas into which the zodiac is
       divided [syn: sign of the zodiac, star sign, sign,
       mansion, house, planetary house]
    6: (medicine) any objective evidence of the presence of a
       disorder or disease; "there were no signs of asphyxiation"
    7: having an indicated pole (as the distinction between positive
       and negative electric charges); "he got the polarity of the
       battery reversed"; "charges of opposite sign" [syn:
       polarity, sign]
    8: an event that is experienced as indicating important things
       to come; "he hoped it was an augury"; "it was a sign from
       God" [syn: augury, sign, foretoken, preindication]
    9: a gesture that is part of a sign language
    10: a fundamental linguistic unit linking a signifier to that
        which is signified; "The bond between the signifier and the
        signified is arbitrary"--de Saussure
    11: a character indicating a relation between quantities; "don't
        forget the minus sign"
    v 1: mark with one's signature; write one's name (on); "She
         signed the letter and sent it off"; "Please sign here"
         [syn: sign, subscribe]
    2: approve and express assent, responsibility, or obligation;
       "All parties ratified the peace treaty"; "Have you signed
       your contract yet?" [syn: sign, ratify]
    3: be engaged by a written agreement; "He signed to play the
       casino on Dec. 18"; "The soprano signed to sing the new
       opera"
    4: engage by written agreement; "They signed two new pitchers
       for the next season" [syn: sign, contract, sign on,
       sign up]
    5: communicate silently and non-verbally by signals or signs;
       "He signed his disapproval with a dismissive hand gesture";
       "The diner signaled the waiters to bring the menu" [syn:
       sign, signal, signalize, signalise]
    6: place signs, as along a road; "sign an intersection"; "This
       road has been signed"
    7: communicate in sign language; "I don't know how to sign, so I
       could not communicate with my deaf cousin"
    8: make the sign of the cross over someone in order to call on
       God for protection; consecrate [syn: bless, sign]

Moby Thesaurus II by Grady Ward, 1.0:

536 Moby Thesaurus words for "sign":
   OK, Roman candle, abandon, abnormality, accent, accent mark,
   accept, accredit, acute disease, adumbration, advertisement,
   affection, affirm, affliction, agent, agree on terms,
   aid to navigation, ailment, alarm, allergic disease, allergy,
   alphabet, alphabetic character, alphabetize, alternate,
   alternative, amber light, amen, analogy, announcement, approve,
   assign, assure, atrophy, attest, attestation, augury, auspice,
   authenticate, authorize, autograph, back, backup,
   bacterial disease, badge, balefire, banner, bar, basis for belief,
   be sponsor for, beacon, beacon fire, beat the drum, bell,
   bell buoy, betokening, betokenment, binary digit, birth defect,
   bit, blight, blinker, blue peter, body of evidence, bond, brand,
   broad hint, broadside, buoy, cancel, capitalize,
   cardiovascular disease, cartouche, caution light, certify,
   chain of evidence, change, changeling, character, characteristic,
   chronic disease, cipher, circulatory disease, close down, clue,
   colophon, comparison, complaint, complication, condensation trail,
   condition, confirm, congenital defect, consign, contract, contrail,
   copy, cosign, counterfeit, countersecure, countersign, course, cue,
   custos, cypher, data, datum, defect, deficiency disease, deformity,
   degenerative disease, deliver, deputy, device, differentia, digit,
   dip, direct, disability, disease, disorder, dispose of, distemper,
   documentation, donate, dot, double, dummy, earmark, emblem, employ,
   enchantment, endemic, endemic disease, endocrine disease, endorse,
   engage, enlist, ensign, ensure, epidemic disease, equal,
   equivalent, ersatz, evidence, exchange, exchange colors, exhibit,
   exponent, expression mark, fact, facts, fake, fantasy, fermata,
   figure, fill-in, flag, flag down, flare, flash, fog bell,
   fog signal, fog whistle, foghorn, foreboding, foreshadow,
   foreshadowing, foreshowing, foretoken, foretokening, forewarning,
   forgo, formalize, functional disease, fungus disease,
   gastrointestinal disease, genetic disease, gentle hint,
   gesticulation, gesture, get rid of, ghost, ghostwriter, give,
   give a signal, give permission, give the go-ahead,
   give the imprimatur, give the nod, give thumbs up, give up, glance,
   glimmer, glimmering, glosseme, go light, gong buoy, graph,
   grapheme, green light, grounds, grounds for belief, guarantee,
   guaranty, hail, hail and speak, half-mast, hallmark, handicap,
   heliograph, hereditary disease, hieroglyph, high sign, hint, hire,
   hoist a banner, hold, iatrogenic disease, icon, ideogram,
   ideograph, idiosyncrasy, illness, image, imitation, implication,
   index, indicant, indication, indicator, indisposition,
   infectious disease, infirmity, initial, initials, ink, inkling,
   innuendo, inscribe, insignia, insinuation, insure,
   international alphabet flag, international numeral pennant,
   intimation, item of evidence, join up, key signature, keynote,
   kick, lead, leer, letter, lexeme, lexical form,
   lexigraphic character, ligature, line, locum tenens, logotype,
   look, make a sign, make over, makeshift, malady, malaise,
   manifestation, mark, marker beacon, material grounds, measure,
   metaphor, metonymy, metronomic mark, miracle, monogram, morbidity,
   morbus, morpheme, motion, movement, muniments, muscular disease,
   mute witness, neurological disease, next best thing, nod, notarize,
   notation, note, notice, nudge, number, numeral, numero,
   nutritional disease, occupational disease, omen, organic disease,
   pandemic disease, parachute flare, pass, pass on, pass upon, path,
   pathological condition, pathology, pause, peculiarity, permit,
   personnel, phonetic character, phonetic symbol, phony, phrase,
   pictographic character, picture, piece of evidence, pilot flag,
   pinch hitter, piste, placard, plant disease, poke, police whistle,
   portent, poster, prefiguration, preindication, premises,
   premonitory shiver, premonitory sign, premonitory symptom, presa,
   present, presignifying, prodigy, prognosis, prognostic,
   prognostication, promise, prompt, proof, property, prophecy,
   protozoan disease, proxy, psychosomatic disease, quarantine flag,
   radio beacon, raise a cry, ratify, reason to believe, rebus,
   red flag, red light, register, release, relevant fact, relief,
   relinquish, reminder, replacement, representation, representative,
   reserves, respiratory disease, retain, ringer, rocket, rockiness,
   rubber stamp, sacrifice, sailing aid, salute, sanction,
   say amen to, scent, seal, second, second string, secondary,
   secondary disease, secure, seediness, segno, semaphore,
   semaphore flag, semaphore telegraph, semasiological unit, sememe,
   shadow, shake hands, shingle, show, sickishness, sickness, sigil,
   sign and seal, sign away, sign for, sign off, sign on, sign over,
   sign up, sign up for, signal, signal beacon, signal bell,
   signal fire, signal flag, signal gong, signal gun, signal lamp,
   signal light, signal mast, signal post, signal rocket, signal shot,
   signal siren, signal tower, signalize, signature, signboard,
   signifiant, significant, signs, slur, soothsay, sound an alarm,
   sound the trumpet, spar buoy, spares, speak, sponsor, spoor, stamp,
   stand behind, stand up for, stand-in, standard, stop light,
   strike a bargain, sub, subscribe, subscribe to, substituent,
   substitute, substitution, succedaneum, suggestion, superseder,
   supplanter, support, sure sign, surrender, surrogate, suspicion,
   swear and affirm, swear to, swell, syllabic, symbol, symbolization,
   symptom, symptomatology, symptomology, symptoms, syndrome,
   synecdoche, take on, telltale, telltale sign, tempo mark, term,
   the nod, the pip, the wink, third string, tie, time signature,
   token, tokening, touch, trace, traces, track, traffic light,
   traffic signal, trail, trait, transcribe, transfer, transliterate,
   turn over, type, undersign, understudy, underwrite, unfurl a flag,
   urogenital disease, utility player, validate, vapor trail, vestige,
   vicar, vice-president, vice-regent, vinculum, virus disease, visa,
   vise, volunteer, waive, wake, warning, warrant, wasting disease,
   watch fire, wave, wave a flag, wave the hand, whisper, white flag,
   wigwag, wigwag flag, wink, witness, wonder, wonderwork, word,
   worm disease, writing, written character, yellow flag



Bouvier's Law Dictionary, Revised 6th Ed (1856):

SIGN, contracts, evidence. A token of anything; a note or token given
without words.
     2. Contracts are express or implied. The express are manifested viva
voce, or by writing; the implied are shown by silence, by acts, or by signs.
     3. Among all nations find and at all times, certain signs have been
considered as proof of assent or dissent; for example, the nodding of the
head, and the shaking of hands; 2 Bl. Com. 448; 6 Toull. D. 33; Heinnec.,
Antiq. lib. 3, t. 23, n. 19; silence and inaction, facts and signs are
sometimes very strong evidence of cool reflection, when following a
question. I ask you to lend me one hundred dollars, without saying a word
you put your hand in your pocket, and deliver me the money. I go into a
hotel and I ask the landlord if he can accommodate me and take care of my
trunk; without speaking he takes it out of my hands and sends it into his
chamber. By this act he doubtless becomes responsible to me as a bailee. At
the expiration of a lease, the tenant remains in possession, without any
objection from the landlord; this may be fairly interpreted as a sign of a
consent that the lease shall be renewed. 13 Serg. & Rawle, 60.
     4, The learned author of the Decline and Fall of the Roman Empire, in
his 44th chapter, remarks, "Among savage nations, the want of letters is
imperfectly supplied by the use of visible signs, which awaken attention,
and perpetuate the remembrance of any public or private transaction. The
jurisprudence of the first Romans exhibited the scenes of a pantomime; the
words were adapted to the gestures, and the slightest error or neglect in
the forms of proceeding was sufficient to annul the substance of the fairest
claim. The communion of the marriage-life was denoted by the necessary
elements of fire and water: and the divorced wife resigned, the bunch of
keys, by the delivery of which she had been invested with the government of
the family. The manumission of a son, or a slave, was performed by turning
him round with a gentle blow on the cheek: a work was prohibited by the
casting of a stone; prescription was interrupted by the breaking of a
branch; the clenched fist was the symbol of a pledge or deposits; the right
hand was the gift of faith and confidence. The indenture of covenants was a
broken straw; weights and, scales were introduced into every payment, and
the heir who accepted a testament, was sometimes obliged to snap his
fingers, to cast away his garments, and to leap and dance with real or
affected transport. If a citizen pursued any stolen goods into a neighbor's
house, he concealed his nakedness with a linen towel, and hid his. face with
a mask or basin, lest he should encounter the eyes of a virgin or a matron.
In a civil action, the plaintiff touched the ear of his witness seized his
reluctant adversary by the neck and implored, in solemn lamentation, the aid
of his fellow citizens. The two competitors grasped each other's hand, as if
they stood prepared for combat before the tribunal of the praetor: he
commanded them to produce the object of the dispute; they went, they
returned with measured steps, and a clod of earth was cast at his feet to
represent the field for which they contended. This occult science of the
words and actions of law, was the inheritance of the pontiffs and
patricians. Like the Chaldean astrologers, they announced to their clients
the days of business and repose; these important trifles wore interwoven
with the religion of Numa; and, after the publication of the Twelve Tables,
the Roman people were still enslaved by the ignorance of judicial
proceedings. The treachery of some plebeian officers at length revealed the
profitable mystery: in a more enlightened age, the legal actions were
derided and observed; and the same antiquity which sanctified the practice,
obliterated the use and meaning, of this primitive language."



Bouvier's Law Dictionary, Revised 6th Ed (1856):

SIGN, measures. In angular measures, a sign is equal to thirty degrees. Vide
Measure.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

SIGN, mer. law. A board, tin or other substance, on which is painted the
name and business of a merchant or tradesman.
     2. Every man has a right to adopt such a sign as he may please to
select, but he has no right to use another's name, without his consent. See
Dall. Dict. mot Propriete Industrielle, and the article Trade marks.

To SIGN. To write one's name to an instrument of writing in order to give
the effect intended; the name thus written is called a signature.
     2. The signature is usually made at the bottom of the instrument but in
wills it has been held that when a testator commenced his will With these
words;, "I, A B, make this my will," it was a sufficient signing. 3 Lev. 1;
and vide Rob. on Wills, 122 1 Will. on Wills, 49, 50; Chit. Cont. 212 Newl.
Contr. 173; Sugd. Vend. 71; 2 Stark. Ev. 605, 613; Rob. on Fr. 121; but this
decision is said to be absurd. 1 Bro. Civ. Law, 278, n. 16. Vide Merl.
Repert. mot Signature, for a history of the origin, of signatures; and also
4 Cruise, Dig. h.t. 32, c. 2, s. 73, et seq.; see, generally, 8 Toull. n.
94-96; 1 Dall. 64; 5 Whart. R. 386; 2 B. & P 238; 2 M. & S. 286.
     3. To sign a judgment, is to enter a judgment for want of something
which was required to be done; as, for example, in the English practice, if
he who is bound to give oyer does not give it within the time required, in
such cases, the adverse party may sign judgment against him. 2 T. R. 40;
Com. Dig. Pleader, P 1; Barnes, 245.