The Collaborative International Dictionary of English v.0.48:

Conjugate \Con"ju*gate\, a. [L. conjugatus, p. p. or conjugare
   to unite; con- + jugare to join, yoke, marry, jugum yoke;
   akin to jungere to join. See Join.]
   1. United in pairs; yoked together; coupled.
      [1913 Webster]

   2. (Bot.) In single pairs; coupled.
      [1913 Webster]

   3. (Chem.) Containing two or more compounds or radicals
      supposed to act the part of a single one. [R.]
      [1913 Webster]

   4. (Gram.) Agreeing in derivation and radical signification;
      -- said of words.
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   5. (Math.) Presenting themselves simultaneously and having
      reciprocal properties; -- frequently used in pure and
      applied mathematics with reference to two quantities,
      points, lines, axes, curves, etc.
      [1913 Webster]

   Conjugate axis of a hyperbola (Math.), the line through the
      center of the curve, perpendicular to the line through the
      two foci.

   Conjugate diameters (Conic Sections), two diameters of an
      ellipse or hyperbola such that each bisects all chords
      drawn parallel to the other.

   Conjugate focus (Opt.) See under Focus.

   Conjugate mirrors (Optics), two mirrors so placed that rays
      from the focus of one are received at the focus of the
      other, especially two concave mirrors so placed that rays
      proceeding from the principal focus of one and reflected
      in a parallel beam are received upon the other and brought
      to the principal focus.

   Conjugate point (Geom.), an acnode. See Acnode, and
      Double point.

   Self-conjugate triangle (Conic Sections), a triangle each
      of whose vertices is the pole of the opposite side with
      reference to a conic.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Conjugate \Con`ju*gate\, n. [L. conjugatum a combining,
   etymological relationship.]
   1. A word agreeing in derivation with another word, and
      therefore generally resembling it in signification.
      [1913 Webster]

            We have learned, in logic, that conjugates are
            sometimes in name only, and not in deed. --Abp.
                                                  Bramhall.
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   2. (Chem.) A complex compound formed from the non-covalent
      union of two other comounds, behaving as a single
      compound. [R.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Conjugate \Con"ju*gate\, v. t. [imp. & p. p. Conjugated; p.
   pr. & vb. n. Conjugating.]
   1. To unite in marriage; to join. [Obs.] --Sir H. Wotton.
      [1913 Webster]

   2. (Gram.) To inflect (a verb), or give in order the forms
      which it assumes in its several voices, moods, tenses,
      numbers, and persons.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Conjugate \Con"ju*gate\, v. i. (Biol.)
   To unite in a kind of sexual union, as two or more cells or
   individuals among the more simple plants and animals.
   [1913 Webster]

WordNet (r) 3.0 (2006):

conjugate
    adj 1: joined together especially in a pair or pairs [syn:
           conjugate, conjugated, coupled]
    2: (of a pinnate leaflet) having only one pair of leaflets
    3: formed by the union of two compounds; "a conjugated protein"
       [syn: conjugate, conjugated]
    4: of an organic compound; containing two or more double bonds
       each separated from the other by a single bond [syn:
       conjugate, conjugated]
    n 1: a mixture of two partially miscible liquids A and B
         produces two conjugate solutions: one of A in B and another
         of B in A [syn: conjugate solution, conjugate]
    v 1: unite chemically so that the product is easily broken down
         into the original compounds
    2: add inflections showing person, number, gender, tense,
       aspect, etc.; "conjugate the verb"
    3: undergo conjugation

Moby Thesaurus II by Grady Ward, 1.0:

150 Moby Thesaurus words for "conjugate":
   accouple, accumulate, affiliate, affiliated, agglutinate, allied,
   amalgamated, amass, analyze, articulate, assemble, assimilated,
   associate, associated, band, biconjugate, bigeminate, bijugate,
   blended, bond, bound, bracket, bracketed, bridge, bridge over,
   cement, chain, clap together, coalesce, coincident, collateral,
   collect, combinative, combinatory, combine, combined, compact,
   comprehensive, comprise, concatenate, concurrent, conglobulate,
   conjoin, conjoint, conjugated, conjunct, conjunctive, connect,
   connected, connective, consolidated, copulate, corporate,
   correlated, couple, couple up, coupled, cover, decline, derivative,
   double-harness, double-team, echoic, eclectic, embrace, encompass,
   etymologic, fused, gather, glue, hyphenate, implicated, include,
   inclusive, incorporated, inflect, integrated, interlinked,
   interlocked, interrelated, involved, join, joined, joint, knot,
   knotted, lay together, league, lexical, lexicographic, lexicologic,
   lexigraphic, link, linked, lump together, mark, marry, marshal,
   mass, match, matched, mate, mated, merge, merged, mixed, mobilize,
   of that ilk, of that kind, one, onomastic, onomatologic,
   onomatopoeic, pair, pair off, paired, parallel, parenthesize,
   paronymic, paronymous, parse, piece together, point, punctuate,
   put together, related, roll into one, solder, span, splice,
   spliced, stick together, syncretistic, syncretized, synthesized,
   take in, tape, team, team up, tie, tied, twinned, unify, unite,
   united, wed, wedded, weld, yoke, yoked