The Collaborative International Dictionary of English v.0.48:

Conjugation \Con`ju*ga"tion\, n. [L. conjugatio conjugation (in
   senses 1 & 3).]
   1. the act of uniting or combining; union; assemblage. [Obs.]
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            Mixtures and conjugations of atoms.   --Bentley.
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   2. Two things conjoined; a pair; a couple. [Obs.]
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            The sixth conjugations or pair of nerves. --Sir T.
                                                  Browne.
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   3. (Gram.)
      (a) The act of conjugating a verb or giving in order its
          various parts and inflections.
      (b) A scheme in which are arranged all the parts of a
          verb.
      (c) A class of verbs conjugated in the same manner.
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   4. (Biol.) A kind of sexual union; -- applied to a blending
      of the contents of two or more cells or individuals in
      some plants and lower animals, by which new spores or
      germs are developed.
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WordNet (r) 3.0 (2006):

conjugation
    n 1: the state of being joined together [syn: junction,
         conjunction, conjugation, colligation]
    2: the inflection of verbs
    3: the complete set of inflected forms of a verb
    4: a class of verbs having the same inflectional forms
    5: the act of pairing a male and female for reproductive
       purposes; "the casual couplings of adolescents"; "the mating
       of some species occurs only in the spring" [syn: coupling,
       mating, pairing, conjugation, union, sexual union]
    6: the act of making or becoming a single unit; "the union of
       opposing factions"; "he looked forward to the unification of
       his family for the holidays" [syn: union, unification,
       uniting, conjugation, jointure] [ant: disunion]