Composed of three parts; threefold; triple.
Having three apartments, divisions, or floors: a triplex apartment building; a triplex cinema.
Something, such as an apartment building, that is triplex: We live in a triplex.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.