1. (a.) Compounded or consisting of two things or parts; characterized by two (things).

2. (n.) That which is constituted of two figures, things, or parts; two; duality.

Janus-like ambidextrous bifacial bifold biform bilateral binate biparous bivalent conduplicate disomatous double double-barreled double-faced dual dualistic duple duplex duplicate geminate geminated second secondary twin twinned two-faced two-level two-ply two-sided two-story twofold