THESAURUS
Janus-like, ambidextrous, as much again, bifacial, bifold, biform, bilateral, binary, binate, biparous, bivalent, conduplicate, disomatous, double, double-barreled, double-faced, doubly, dual, dualistic, dually, duple, duplex, duplicate, dyadic, geminate, geminated, paired, second, secondary, twice, twice as much, twice over, twin, twinned, two times, two-faced, two-level, two-ply, two-sided, two-story
ROGET THESAURUS
Duplication
N
duplication, doubling, gemination, ingemination, reduplication, iteration, renewal, double, doubled, bicipital, bicephalous, bidental, bilabiate, bivalve, bivalvular, bifold, biform, bilateral, bifarious, bifacial, twofold, two-sided, disomatous, duplex, double-faced, double-headed, twin, duplicate, ingeminate, second, twice, once more, over again, as much again, twofold, secondly, in the second place, again,
duplication, doubling, gemination, ingemination, reduplication, iteration, renewal, double, doubled, bicipital, bicephalous, bidental, bilabiate, bivalve, bivalvular, bifold, biform, bilateral, bifarious, bifacial, twofold, two-sided, disomatous, duplex, double-faced, double-headed, twin, duplicate, ingeminate, second, twice, once more, over again, as much again, twofold, secondly, in the second place, again.