Definitions of enter:

• verb:   become a participant; be involved in

  Example: "Enter a race"

• verb:   come on stage
• verb:   to come or go into

  Example: "The boat entered an area of shallow marshes"

• verb:   take on duties or office
• verb:   be or play a part of or in
• verb:   set out on (an enterprise, subject of study, etc.)
• verb:   make a record of; set down in permanent form
• verb:   register formally as a participant or member
• verb:   put or introduce into something
• name:  A surname (very rare: popularity rank in the U.S.: #57410)