Synonyms and related words :
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