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.