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.