- in two, into two separate parts, as halves. 2. put two and two together, to reach the correct and obvious conclusion. Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
From Middle English two, twa, from Old English twā, feminine and neuter of twēġen (whence twain), from Proto-West Germanic *twai-, from Proto-Germanic *twai, from Proto-Indo-European *dwóh₁.