Real Dictionary

enter
verb: If something new enters your mind, you suddenly think about it.
verb: If you enter an organization or institution, you start to work there or become a member of it.
verb: When you enter a place such as a room or building, you go into it or come into it.

enter in American English
to come or go in or into
intransitive verb: to come or go in
transitive verb: to come or go into

enter in British English
verb: to come or go into (a place, house, etc)

enter- in American English
combining form