What does "enter" mean?

Additional senses

1. 2.To engage in; to become occupied with; as, to enter the legal profession, the book trade, etc.
2. 3.To pass within the limits of; to attain; to begin; to commence upon; as, to enter one's teens, a new era, a new dispensation.
3. 4.To cause to go (into), or to be received (into); to put in; to insert; to cause to be admitted; as, to enter a knife into a piece of wood, a wedge into a log; to enter a boy at college, a horse for a race, etc.
4. 5.To inscribe; to enroll; to record; as, to enter a name, or a date, in a book, or a book in a catalogue; to enter the particulars of a sale in an account, a manifest of a ship or of merchandise at the customhouse.
5. 6.(Law) (a) To go into or upon, as lands, and take actual possession of them. (b) To place in regular form before the court, usually in writing; to put upon record in proper from and order; as, to enter a writ, appearance, rule, or judgment. Burrill.
6. 7.To make report of (a vessel or her cargo) at the customhouse; to submit a statement of (imported goods), with the original invoices, to the proper officer of the customs for estimating the duties. See Entry, 4.
7. 8.To file or inscribe upon the records of the land office the required particulars concerning (a quantity of public land) in order to entitle a person to a right pf preëmption. [U.S.] Abbott.
8. 9.To deposit for copyright the title or description of (a book, picture, map, etc.); as, "entered according to act of Congress."
9. 10.To initiate; to introduce favorably. [Obs.] Shak.
10. 11.To go or come in; -- often with in used pleonastically; also, to begin; to take the first steps. "The year entering." Evelyn. No evil thing approach nor enter in. Milton. Truth is fallen in the street, and equity can not enter. Is. lix.
11. 12.For we which have believed do enter into rest. Heb. iv.
12. 13.2. To get admission; to introduce one's self; to penetrate; to form or constitute a part; to become a partaker or participant; to share; to engage; -- usually with into; sometimes with on or upon; as, a ball enters into the body; water enters into a ship; he enters into the plan; to enter into a quarrel; a merchant enters into partnership with some one; to enter upon another's land; the boy enters on his tenth year; to enter upon a task; lead enters into the composition of pewter.
13. 14.To penetrate mentally; to consider attentively; -- with into. He is particularly pleased with . . . Sallust for his entering into internal principles of action. Addison.