En-

1.
a prefix occurring originally in loanwords from French and productive in English on this model, forming verbs with the general sense “to cause (a person or thing) to be in” the place, condition, or state named by the stem; more specifically, “to confine in or place on” (enshrine; enthrone; entomb); “to cause to be in” (enslave; entrust; enrich; encourage; endear); “to restrict” in the manner named by the stem, typically with the additional sense “on all sides, completely” (enwind; encircle; enclose; entwine). This prefix is also attached to verbs in order to make them transitive, or to give them a transitive marker if they are already transitive (enkindle; enliven; enshield; enface).
1.
a prefix meaning “within, in,” occurring in loanwords from Greek:
energy; enthusiasm.
prefix
1.
(from nouns)

2.
(from adjectives and nouns) cause to be in a certain condition: enable, encourage, enrich, enslave
prefix
1.
in; into; inside: endemic

assimilated to -p-, -b-, -m-, -l-, -r-, word-forming element meaning “in, into,” from French and Old French en-, from Latin in- “in, into” (see in- (2)).

Also used with native elements to form verbs from nouns and adjectives, “put in or on” (encircle), also “cause to be, make” (endear), and used as an intensive (enclose). Spelling variants in French that were brought over into Middle English account for parallels such as assure/ensure/insure.

assimilated to -p-, -b-, -m-, -l-, -r-, word-forming element meaning “near, at in, on, within,” from Greek en “in,” cognate with Latin in (see in), and with en- (1).

en- 2 or em-
pref.
In; into; within: enzootic.