ENGAGE (2)

En‐gage″, v. i. 1. 1. To promise or pledge one's self; to enter into an obligation; to become bound; to warrant.
How proper the remedy for the malady, I engage not. Fuller. 2. 2. To embark in a business; to take a part; to employ or involve one's self; to devote attention and effort; to enlist; as, to engage in controversy.
3. 3. To enter into conflict; to join battle; as, the armies engaged in a general battle.
4. 4. (Mach.) To be in gear, as two cogwheels working together.