The Collaborative International Dictionary of English v.0.48:

frank \frank\ (fr[a^][ng]k), v. t. [imp. & p. p. franked
   (fr[a^][ng]kt); p. pr. & vb. n. franking.]
   1. To send by public conveyance free of expense. --Dickens.
      [1913 Webster]

   2. To extempt from charge for postage, as a letter, package,
      or packet, etc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Frank \Frank\, n. [See Frank, a.]
   The privilege of sending letters or other mail matter, free
   of postage, or without charge; also, the sign, mark, or
   signature denoting that a letter or other mail matter is to
   go free of postage. Called also the franking privilege.
   [1913 Webster +PJC]

         I have said so much, that, if I had not a frank, I must
         burn my letter and begin again.          --Cowper.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Frank \Frank\, n. [OF. franc.]
   A pigsty. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Frank \Frank\, v. t.
   To shut up in a frank or sty; to pen up; hence, to cram; to
   fatten. [Obs.] --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Frank \Frank\, n. (Zool.)
   The common heron; -- so called from its note. [Prov. Eng.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

frank \frank\ (fr[a^][ng]k), a. [Compar. franker
   (fr[a^][ng]k"[~e]r); superl. frankest.] [F. franc free,
   frank, L. Francus a Frank, fr. OHG. Franko the name of a
   Germanic people on the Rhine, who afterward founded the
   French monarchy; cf. AS. franca javelin, Icel. frakka. Cf.
   Franc, French, a., Franchise, n.]
   1. Unbounded by restrictions, limitations, etc.; free. [R.]
      "It is of frank gift." --Spenser.
      [1913 Webster]

   2. Free in uttering one's real sentiments; not reserved;
      using no disguise; candid; ingenuous; as, a frank nature,
      conversation, manner, etc.
      [1913 Webster]

   3. Liberal; generous; profuse. [Obs.]
      [1913 Webster]

            Frank of civilities that cost them nothing.
                                                  --L'Estrange.
      [1913 Webster]

   4. Unrestrained; loose; licentious; -- used in a bad sense.
      --Spenser.

   Syn: Ingenuous; candid; artless; plain; open; unreserved;
        undisguised; sincere. See Candid, Ingenuous.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Frank \Frank\, n. [Cf. F. franc. See Frank, a.]
   1. (Ethnol.) A member of one of the German tribes that in the
      fifth century overran and conquered Gaul, and established
      the kingdom of France.
      [1913 Webster]

   2. A native or inhabitant of Western Europe; a European; -- a
      term used in the Levant.
      [1913 Webster]

   3. A French coin. See Franc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

frank
    adj 1: characterized by directness in manner or speech; without
           subtlety or evasion; "blunt talking and straight
           shooting"; "a blunt New England farmer"; "I gave them my
           candid opinion"; "forthright criticism"; "a forthright
           approach to the problem"; "tell me what you think--and
           you may just as well be frank"; "it is possible to be
           outspoken without being rude"; "plainspoken and to the
           point"; "a point-blank accusation" [syn: blunt,
           candid, forthright, frank, free-spoken,
           outspoken, plainspoken, point-blank, straight-
           from-the-shoulder]
    2: clearly manifest; evident; "frank enjoyment"
    n 1: a member of the ancient Germanic peoples who spread from
         the Rhine into the Roman Empire in the 4th century
    2: a smooth-textured sausage of minced beef or pork usually
       smoked; often served on a bread roll [syn: frank,
       frankfurter, hotdog, hot dog, dog, wiener,
       wienerwurst, weenie]
    v 1: stamp with a postmark to indicate date and time of mailing
         [syn: postmark, frank]
    2: exempt by means of an official pass or letter, as from
       customs or other checks

Moby Thesaurus II by Grady Ward, 1.0:

213 Moby Thesaurus words for "frank":
   PP, RD, RFD, Spartan, Vienna sausage, accessible, airmail, all jaw,
   approachable, artless, ascetic, austere, bald, bangers, bare,
   barefaced, black pudding, blood pudding, bluff, blunt, bologna,
   book post, born yesterday, braunschweiger, brazen, broad, brusque,
   cancellation, candid, chatty, childlike, coarse, common,
   commonplace, communicative, confiding, conversable, conversational,
   correspondence, demonstrative, direct, direct mail,
   direct-mail selling, dispassionate, dog, downright, dry, dull,
   earthy, effusive, expansive, explicit, express, extroverted, fair,
   flip, fluent, forthright, fourth-class mail, frankfurter,
   frankhearted, free, free-speaking, free-spoken, free-tongued,
   gabby, garrulous, gassy, genuine, glib, gooseliver, gossipy,
   gregarious, gross, guileless, gushy, gutter, halfpenny post,
   headcheese, heart-to-heart, homely, homespun, honest, hot dog,
   impartial, ingenu, ingenuous, innocent, junk mail, just,
   knockwurst, lean, letter post, letters, liver sausage, liverwurst,
   long-winded, loquacious, low, mail, mail-order selling,
   mailing list, matter-of-fact, multiloquent, multiloquious, naive,
   natural, neat, newspaper post, newsy, on the level, open,
   openhearted, outgoing, outspoken, overtalkative, parcel post,
   plain, plain-speaking, plain-spoken, plainspoken, post, post day,
   postage, postage stamp, postmark, prolix, prosaic, prosing, prosy,
   pure, rank, raw, registered mail, round, rural delivery,
   rural free delivery, rustic, salami, saucisse, sausage, scrupulous,
   sea mail, seapost, self-revealing, self-revelatory, severe, simple,
   simple-speaking, simplehearted, simpleminded, sincere, single,
   single-hearted, single-minded, smooth, sober, sociable, spare,
   special delivery, special handling, stamp, stark, straight,
   straight-out, straightforward, surface mail, talkative, talky,
   transparent, trustful, trusting, truthful, unabashed, unadorned,
   unaffected, unbiased, unchecked, unconcealed, unconstrained,
   uncouth, undisguised, undissembled, undissembling, unequivocal,
   unguarded, unhampered, unimaginative, uninhibited, unmannered,
   unpoetical, unrepressed, unreserved, unrestrained, unrestricted,
   unreticent, unsecretive, unshrinking, unsilent, unsophisticated,
   unsuppressed, unsuspicious, unvarnished, unwary, upright, verbose,
   voluble, vulgar, weenie, wiener, wienerwurst, wienie, windy



The Free On-line Dictionary of Computing (30 December 2018):

FRANK

   ["Using BINS for Interprocess Communication", P.C.J. Graham,
   SIGPLAN Notices 20(2):32-41 (Feb 1985)].

   (1995-01-13)


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

FRANK. The privilege of sending and receiving letters, through the mails,
free of postage.
     2. This privilege is granted to various officers, not for their own
special benefit, but with a view to promote the public good.
     3. The Act of the 3d of March, 1845, s. 1, enacts, That members of
congress, and delegates from the territories, may receive letters, not
exceeding two ounces in weight, free of postage, during the recess of
congress; and the same privilege is extended to the vice-president of the
United States.
     4. It is enacted, by 3d section, That all printed or lithographed
circulars and handbills, or advertisements, printed or lithographed, on
quarto post or single cap paper, or paper not larger than single cap,
folded, directed, and unsealed, shall be charged with postage, at the rate
of two cents for each sheet, and no more, whatever be the distance the same
may be sent; and all pamphlets, magazines, periodicals, and every other kind
and description of printed or other matter, (except newspapers,) which shall
be unconnected with any manuscript communication whatever, and which it is
or may be lawful to transmit by the mail of the United States, shall be
charged with postage, at the rate of two and a half cents for each copy
sent, of no greater weight than one ounce, and one cent additional shall be
charged for each additional ounce of the weight of every such pamphlet,
magazine, matter, or thing, which may be transmitted through the mail,
whatever be the distance the tame may be transported and any fractional
excess, of not less than one-half of an ounce, in the weight of any such
matter or thing, above one or more ounces, shall be charged for as if said
excess amounted to a full ounce.
     5. And, by the 8th section, That each member of the senate, each member
of the house of representatives, and each delegate from a territory of the
United States, the secretary of the senate, and the clerk of the house, of
representatives, may, during each session of congress, and for a period of
thirty days before the commencement, and thirty days after the end of each
and every session of congress, Bend and receive through the mail, free of
postage, any letter, newspaper, or packet, not exceeding two ounces in
weight; and all postage charged upon any letters, packages, petitions
memorials, or other matters or things, received during any session of
congress, by any senator, member, or delegate of the house of
representatives, touching his official or legislative duties, by reason of
any excess of weight, above two ounces, on the matter or thing so received,
shall be paid out of the contingent fund of the house of which the person
receiving the same may be a member. And they shall have the right to frank
written letters from themselves during the whole year, as now authorized by
law.
     6. The 5th section repeals all acts, and parts of acts, granting or
conferring upon any person whatsoever the franking privilege.
     7. The 23d section enacts, That nothing in this act contained shall be
construed to repeal the laws granting the franking privilege to the
president of the United States when in office, and to all ex-presidents, and
the widows of the former presidents, Madison and Harrison.
     8. The Act of March 1, 1847, enacts as follows
     Sec. 3. That all members of Congress, delegates from territories, the
vice-president of the United States, the secretary of the senate, and the
clerk of the house of representatives, shall have the power to send and
receive public documents free of postage during their term of office; and
that the said members and delegates shall have the power to send and receive
public documents, free of Postage, up to the first Monday of December
following the expiration of their term of office.
     Sec. 4. That the secretary of the senate and clerk of the house of
representatives shall have the power to receive, as well as to send, all
letters and packages, not weighing over two ounces, free of postage, during
their term of office.
     Sec. 5. That members of congress shall have the power to receive, as
well as to send, all letters and packages, not weighing over two ounces,
free of postage, up to the first Monday in December following the expiration
of their term of office.



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

FRANK, FREE. This word is used in composition, as frank-almoign, frank-
marriage, frank-tenement, &c.