a prefix occurring in loanwords from Latin, where it meant “between,” “among,” “in the midst of,” “mutually,” “reciprocally,” “together,” “during” (intercept; interest); on this model, used in the formation of compound words (intercom; interdepartmental).
Middle English < Latin (in some words replacing Middle Englishentre- < Middle French < Latininter-), combining form of inter (preposition and adv.); see interior
c.1300, from O.Fr. enterer, from M.L. interrare "put in the earth, bury," from L. in- "in" + terra "earth" (see terrain).
L. inter (prep., adj.) "among, between," from PIE *enter "between, among" (cf. Skt. antar, O.Pers. antar "among, between," Gk. entera (pl.) "intestines," O.Ir. eter, O.Welsh ithr "among, between," Goth. undar, O.E. under "under"), a comparative of *en- "in." Also in certain L. phrases in Eng., such as inter alia "among other things." Spelled entre- in Fr., most words borrowed into Eng. in that form were re-spelled 16c. to conform with L. except entertain, enterprise.