mid-15c., from Latin conectere "join together" (see connection). Displaced 16c. by connex (1540s), from Middle French connexer, from Latin *connexare, a supposed frequentative of conectere (past participle stem connex-). Connect was re-established 1670s.
A similar change took place in French, where connexer was superseded by connecter. Meaning "to establish a relationship" (with) is from 1881. Slang meaning "get in touch with" is attested by 1926, from telephone connections. Meaning "awaken meaningful emotions, establish rapport" is from 1942. Of a hit or blow, "to reach the target," from c.1920. Related: Connected; connecting; connectedness.