To enter into battle.
To enter into conflict with (an enemy).
To come into gear with.
To enter into (an activity), to participate (construed with in).
To draw into conversation.
To mesh or interlock (of machinery, especially a clutch).
To attract, to please; (archaic) to fascinate or win over (someone).
To guarantee or promise (to do something).
To engross or hold the attention of; to keep busy or occupied.
To arrange to employ or use (a worker, a space, etc.).
To bind through legal or moral obligation (to do something, especially to marry) (usually in passive).
To become made ready for war.
To make something mobile.
To assemble troops and their equipment in a coordinated fashion so as to be ready for war.