late 14c., "to connect with," from Old French annexer "to join, attach" (13c.), from Medieval Latin annexare, frequentative of Latin annecetere "to bind to," from ad "to" (see ad-) + nectere "to tie, bind" (from PIE root *ned- "to bind, tie"). Usually meaning "to join in a subordinate capacity," but that notion is not in the etymology. Of nations or territories, c. 1400. Related: Annexed; annexing.