Definition of "Enter" :

verb: set out on (an enterprise or subject of study)

verb: make a record of; set down in permanent form

verb: become a participant; be involved in

"Enter a race."

verb: put or introduce into something

verb: come on stage

verb: to come or go into

"The boat entered an area of shallow marshes."

verb: take on duties or office

verb: register formally as a participant or member

verb: be or play a part of or in