em-1

1.
variant of en-1. before b, p, and sometimes m: embalm.
Compare im-1 .

em-2

1.
variant of en-2. before b, m, p, ph: embolism, emphasis.
British Dictionary definitions for em-

em-

prefix
1.
before b, m, and p, a variant of en-1 , en-2

en-1

prefix
1.
(from nouns)
  1. put in or on: entomb, enthrone
  2. go on or into: enplane
  3. surround or cover with: enmesh
  4. furnish with: empower
2.
(from adjectives and nouns) cause to be in a certain condition: enable, encourage, enrich, enslave
Word Origin
via Old French from Latin in-in-²

en-2

prefix
1.
in; into; inside: endemic
Word Origin
from Greek (often via Latin); compare in-1, in-²
Word Origin and History for em-

from French assimilation of en- to following labial (see en- (1)). Also a prefix used to form verbs from adjectives and nouns.

representing Latin ex- assimilated to following -m- (see ex-).

em- in Medicine

em- pref.
Variant of en-2.