Word Origin & History
prefix meaning "cause to be, make" (endear); "put in or on" (encircle); from O.Fr. en-, from L. in- "in, into." Also used as an intensive (enclose). Spelling variants in O.Fr. brought over into M.E. account for parallels such as assure/insure/ensure. Many words beginning with en- in Mod.Eng. are transparent
(enforce, etc.) and etymologies can be found in listings for their stems. Words listed here include those whose unprefixed form is not an obvious word in Eng. (encroach) or whose meaning has drifted significantly (engrain).