The Collaborative International Dictionary of English v.0.48:

Ternary \Ter"na*ry\, a. [L. ternarius, fr. terni. See Tern,
   a.]
   1. Proceeding by threes; consisting of three; as, the ternary
      number was anciently esteemed a symbol of perfection, and
      held in great veneration.
      [1913 Webster]

   2. (Chem.) Containing, or consisting of, three different
      parts, as elements, atoms, groups, or radicals, which are
      regarded as having different functions or relations in the
      molecule; thus, sodic hydroxide, NaOH, is a ternary
      compound.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ternary \Ter"na*ry\, n.; pl. Ternaries.
   A ternion; the number three; three things taken together; a
   triad.
   [1913 Webster]

         Some in ternaries, some in pairs, and some single.
                                                  --Holder.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ternary
    adj 1: having three units or components or elements; "a ternary
           operation"; "a treble row of red beads"; "overcrowding
           made triple sessions necessary"; "triple time has three
           beats per measure"; "triplex windows" [syn: ternary,
           treble, triple, triplex]
    n 1: the cardinal number that is the sum of one and one and one
         [syn: three, 3, III, trio, threesome, tierce,
         leash, troika, triad, trine, trinity, ternary,
         ternion, triplet, tercet, terzetto, trey, deuce-
         ace]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "ternary":
   clover, deuce-ace, leash, set of three, shamrock, tercet, tern,
   ternal, ternate, ternion, terzetto, three, three-ply, threefold,
   threesome, tierce, treble, trefoil, trey, triad, trialogue,
   triangle, tricorn, trident, triennium, trihedron, trilogic,
   trilogy, trimester, trinal, trine, trinity, trinomial, trio,
   triphthong, triple, triple crown, triple threat, triplet, triplex,
   triplicate, triplopy, tripod, triptych, trireme, triseme,
   triskelion, trisul, triumvirate, triunity, trivet, troika



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

ternary

    A description of an operator taking three
   arguments.  The only common example is C's ?: operator which
   is used in the form "CONDITION ? EXP1 : EXP2" and returns EXP1
   if CONDITION is true else EXP2.  Haskell has a similar "if
   CONDITION then EXP1 else EXP2" operator.

   See also unary, binary.

   (1998-07-29)