en-, em-, el-
(Greek: in, into, inward; within; near, at; to put, to go into, or to cover with; as, entomb, encamp, enfold; to provide with; as, to enlighten; to cause to be; as, to enlarge; thoroughly; as, enmesh; in, within, into; as enzootic)
This prefix, en-, changes to em- before b, p, or ph.