a combining form meaning “two,” used in the formation of compound words: duologue.
Origin of duo-
combining form of Greek dýo, Latin duo two
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British Dictionary definitions for duo-
Word Origin for duo-
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012