enter (Verb) — To come or go into. ex. "the boat entered an area of shallow marshes"
enter (Verb) — Become a participant; be involved in. ex. "enter a race" ex. "enter an agreement" ex. "enter a drug treatment program" ex. "enter negotiations"
enter (Verb) — Register formally as a participant or member.
enter (Verb) — Be or play a part of or in. ex. "Elections enter prominently in every government program"
enter (Verb) — (recording) make a record of; set down in permanent form.
enter (Verb) — (dramaturgy) come on stage.
enter (Verb) — Take on duties or office. ex. "enter to the throne"
enter (Verb) — Place onto or put into something. ex. "enter a picture into the text"
enter (Verb) — Set out on (an enterprise or subject of study). ex. "she entered upon a new career"
enter (Noun) — The key on a computer keyboard that starts a new line when writing text; in other contexts the key usually causes a form or window to perform a default function, e.g. accept the data that has just been input.