The Collaborative International Dictionary of English v.0.48:

Index \In"dex\, n.; pl. E. Indexes, L. Indices(?). [L.: cf.
   F. index. See Indicate, Diction.]
   [1913 Webster]
   1. That which points out; that which shows, indicates,
      manifests, or discloses; as, the increasing unemployment
      rate is an index of how much the economy has slowed.
      [1913 Webster +PJC]

            Tastes are the indexes of the different qualities of
            plants.                               --Arbuthnot.
      [1913 Webster]

   2. That which guides, points out, informs, or directs; a
      pointer or a hand that directs to anything, as the hand of
      a watch, a movable finger or other form of pointer on a
      gauge, scale, or other graduated instrument. In
      (printing), a sign [[hand]] (called also fist) used to
      direct particular attention to a note or paragraph.
      [1913 Webster]

   3. A table for facilitating reference to topics, names, and
      the like, in a book, usually giving the page on which a
      particular word or topic may be found; -- usually
      alphabetical in arrangement, and printed at the end of the
      volume. Typically found only in non-fiction books.
      [1913 Webster +PJC]

   4. A prologue indicating what follows. [Obs.] --Shak.
      [1913 Webster]

   5. (Anat.) The second finger, that next to the pollex
      (thumb), in the manus, or hand; the forefinger; index
      finger.
      [1913 Webster]

   6. (Math.) The figure or letter which shows the power or root
      of a quantity; the exponent. [In this sense the plural is
      always indices.]
      [1913 Webster]

   7. The ratio, or formula expressing the ratio, of one
      dimension of a thing to another dimension; as, the
      vertical index of the cranium.
      [Webster 1913 Suppl.]

   8. A number providing a measure of some quantity derived by a
      formula, usually a form of averaging, from multiple
      quantities; -- used mostly in economics; as, the index of
      leading indicators; the index of industrial production;
      the consumer price index. See, for example, the consumer
      price index.
      [PJC]

   9. (computers) A file containing a table with the addresses
      of data items, arranged for rapid and convenient search
      for the addresses.
      [PJC]

   10. (computers) A number which serves as a label for a data
       item and also represents the address of a data item
       within a table or array.
       [PJC]

   11. (R. C. Ch.), The Index prohibitorius, a catalogue of
       books which are forbidden by the church to be read; also
       called Index of forbidden books and Index Librorum
       Prohibitorum.
       [PJC]

   Index error, the error in the reading of a mathematical
      instrument arising from the zero of the index not being in
      complete adjustment with that of the limb, or with its
      theoretically perfect position in the instrument; a
      correction to be applied to the instrument readings equal
      to the error of the zero adjustment.

   Index expurgatorius. [L.] See Index prohibitorius
      (below).

   Index finger. See Index, 5.

   Index glass, the mirror on the index of a quadrant,
      sextant, etc.

   Index hand, the pointer or hand of a clock, watch, or other
      registering machine; a hand that points to something.

   Index of a logarithm (Math.), the integral part of the
      logarithm, and always one less than the number of integral
      figures in the given number. It is also called the
      characteristic.

   Index of refraction, or Refractive index (Opt.), the
      number which expresses the ratio of the sine of the angle
      of incidence to the sine of the angle of refraction. Thus
      the index of refraction for sulphur is 2, because, when
      light passes out of air into sulphur, the sine of the
      angle of incidence is double the sine of the angle of
      refraction.

   Index plate, a graduated circular plate, or one with
      circular rows of holes differently spaced; used in
      machines for graduating circles, cutting gear teeth, etc.


   Index prohibitorius [L.], or Prohibitory index (R. C.
      Ch.), a catalogue of books which are forbidden by the
      church to be read; the index expurgatorius [L.], or
      expurgatory index, is a catalogue of books from which
      passages marked as against faith or morals must be removed
      before Catholics can read them. These catalogues are
      published with additions, from time to time, by the
      Congregation of the Index, composed of cardinals,
      theologians, etc., under the sanction of the pope. --Hook.

   Index rerum [L.], a tabulated and alphabetized notebook,
      for systematic preservation of items, quotations, etc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Index \In"dex\, v. t. [imp. & p. p. Indexed; p. pr. & vb. n.
   Indexing.]
   1. To provide with an index or table of references; to put
      into an index; as, to index a book, or its contents.
      [1913 Webster]

   2. (Economics) To adjust (wages, prices, taxes, etc.)
      automatically so as to compensate for changes in prices,
      usually as measured by the consumer price index or other
      economic measure. Its purpose is usually to copensate for
      inflation.
      [PJC]

   3. To insert (a word, name, file folder, etc.) into an index
      or into an indexed arrangement; as, to index a contract
      under its date of signing.
      [PJC]

WordNet (r) 3.0 (2006):

index
    n 1: a numerical scale used to compare variables with one
         another or with some reference number
    2: a number or ratio (a value on a scale of measurement) derived
       from a series of observed facts; can reveal relative changes
       as a function of time [syn: index, index number,
       indicant, indicator]
    3: a mathematical notation indicating the number of times a
       quantity is multiplied by itself [syn: exponent, power,
       index]
    4: an alphabetical listing of names and topics along with page
       numbers where they are discussed
    5: the finger next to the thumb [syn: index, index finger,
       forefinger]
    v 1: list in an index
    2: provide with an index; "index the book"
    3: adjust through indexation; "The government indexes wages and
       prices"

Moby Thesaurus II by Grady Ward, 1.0:

432 Moby Thesaurus words for "index":
   Art Index, Baedeker, Bibliography Index, Books in Print,
   Cumulative Book Index, Education Index, Eighteenth Amendment,
   Lambert conformal projection, Mercator projection,
   Miller projection, National Union Catalog, Prohibition Party,
   Volstead Act, Yellow Pages, acknowledgments, aeronautical chart,
   alphabetize, analyze, annotated bibliography, annual bibliography,
   annulary, aroma, arrange, arrow, assort, astronomical chart, atlas,
   attribute, azimuthal equidistant projection, azimuthal projection,
   back, back matter, backlist, badge, ban, banner, bastard title,
   bibliography, bibliography of bibliographies, blaze, book, brand,
   break down, broad hint, business directory, cachet, calendar,
   card index, cartographer, cartography, carve, casebook, cast,
   catalog, catalogue, catalogue raisonne, catch line, catchword,
   categorize, celestial chart, celestial globe, census, chalk,
   chalk up, character, characteristic, chart, check in, checklist,
   chorographer, chorography, chronicle, city directory, class,
   classified catalog, classified directory, classify, climatic chart,
   clue, code, codify, colophon, compass needle, composition,
   concordance, configuration, conic projection, constituents,
   content, contents, contents page, contour line, contour map,
   contraband, copyright page, critical bibliography, cue, cut,
   cyclopedia, cylindrical projection, dactylion, dedication, denial,
   device, diatesseron, dictionary catalog, differentia, differential,
   digest, digit, direction, direction post, directory, disallowance,
   distinctive feature, divide, divisions, docket, earmark, elements,
   embargo, encyclopedia, endleaf, endpaper, endsheet, engrave,
   enroll, enscroll, enter, enumerate, errata, evidence, exclusion,
   factor, feature, figure, figures, file, fill out, finding list,
   finger, finger post, fist, flavor, flyleaf, folio, forbiddance,
   forbidden fruit, forbidding, fore edge, forefinger, foreword,
   formula, front matter, gazetteer, general reference map,
   gentle hint, gesture, glimmer, glimmering, globe,
   gnomonic projection, grade, graphic scale, grave, grid line, group,
   guide, guideboard, guidebook, guidepost, gust, guts, hachure,
   half-title page, hallmark, hand, handbook, handlist, harmony, head,
   heliographic chart, hint, hour hand, hydrographic chart, idiocrasy,
   idiosyncrasy, image, impanel, implication, impress, impression,
   imprint, incise, index expurgatorius, index finger,
   index librorum prohibitorum, indexes, indicant, indication,
   indicator, indices, individualism, ingredients, inhibition,
   injunction, inkling, innards, innuendo, inscribe, inscription,
   insert, insides, insignia, insinuation, interdict, interdiction,
   interdictum, intimation, introduction, inventory, isoline, itemize,
   items, itinerary, jot down, keep score, key, keynote, kick,
   latitude, law, layer tint, lead, leaf, legend, lineaments, list,
   listing, little finger, log, longitude, look, lubber line,
   make a memorandum, make a note, make an entry, make out, makeup,
   mannerism, map, map maker, map projection, mapper, mark, mark down,
   marker, marking, matriculate, measure, medius, meridian,
   middle finger, milepost, minimus, minute, minute hand, mold,
   nature, needle, no-no, nod, note, note down, nudge, odor, order,
   page, parallel, part, particularity, parts, peculiarity,
   periodical index, phone book, photogrammetrist, photogrammetry,
   photomap, phototopography, physical map, picture, pigeonhole,
   pinkie, place, place upon record, pointer, political map, poll,
   pollex, polyconic projection, polyglot, post, post up, preclusion,
   preface, preliminaries, prevention, program, prohibition,
   prohibitory injunction, projection, prompt, property, proscription,
   put down, put in writing, put on paper, put on tape, quality,
   quirk, range, rank, rate, ratio, record, record book, recto,
   reduce to writing, reference book, refusal, register, rejection,
   relief map, representation, representative,
   representative fraction, repression, restrictive covenants,
   reverso, ring finger, road map, roadbook, ruling out,
   running title, savor, scale, scent, schedule, score, seal,
   set down, shape, sigil, sign, signal, signature, signboard,
   significant, signpost, singularity, sinusoidal projection, smack,
   sort, source book, special map, specialty, spoor, stamp,
   statistics, statute, studbook, subdivide, subtitle, suggestion,
   sumptuary laws, suppression, sure sign, suspicion, symptom, table,
   table of contents, table of organization, taboo, tabulate, tail,
   taint, take down, tally, tang, tape, tape-record, taste,
   telephone book, telephone directory, telltale, telltale sign,
   terrain map, terrestrial globe, text, thematic map, thesaurus,
   thumb, thumb index, title, title page, token, topographer,
   topographic chart, topography, track, trait, transportation map,
   trick, trim size, type, type page, verso, videotape,
   vital statistics, weather chart, weather map, whisper, whole, wink,
   work of reference, write, write down, write in, write out,
   write up, zoning, zoning laws



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

index

   (Plural "indices" or "indexes")

   1.  A number used to select an element of a list,
   vector, array or other sequence.  Such indices are nearly
   always non-negative integers but see associative array.

   2.  See inverted index.  [Other kinds?]

   3.  A search engine.

   4.  A subject index.

   [Jargon File]

   (1997-04-09)


U.S. Gazetteer Places (2000):

Index, WA -- U.S. town in Washington
   Population (2000):    157
   Housing Units (2000): 100
   Land area (2000):     0.253094 sq. miles (0.655511 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.253094 sq. miles (0.655511 sq. km)
   FIPS code:            33175
   Located within:       Washington (WA), FIPS 53
   Location:             47.820774 N, 121.553859 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Index, WA
    Index