polarity.
two, deuce, couple, duet, brace, pair, cheeks, twins, Castor and
Pollux, gemini, Siamese twins; fellows; yoke, conjugation; dispermy†,
doublets, dyad, span.
V. pair [unite in pairs], couple, bracket, yoke; conduplicate†; mate,
span [U.S.].
Adj. two, twin; dual, dualistic, double; binary, binomial; twin,
biparous†; dyadic [Math.]; conduplicate†; duplex &c 90; biduous†,
binate†, diphyletic†, dispermic†, unijugate†; tete-a-tete.
coupled &c v.; conjugate.
both, both the one and the other.