engage
v.v. to participate in something or get someone's interest. It can also mean to start a fight or to make parts of a machine fit together.
v. to occupy or attract someone's interest or attention; to participate or become involved in an activity. In a mechanical context, it refers to the interlocking of parts, such as gears, to transmit motion.
The teacher tries to engage the students with a fun game.
The company decided to engage a local law firm to handle the complex merger negotiations.
The pilot waited for the gears to engage fully before increasing the engine power for takeoff, ensuring the mechanical connection was secure.
From Middle English engagen, from Old French engagier (“to pledge, engage”), from Frankish anwadjōn (“to pledge”), from Proto-Germanic an-, andi- + Proto-Germanic wadjōną (“to pledge, secure”), from Proto-Germanic wadją (“pledge, guarantee”), from Proto-Indo-European wedʰ- (“to pledge, redeem a pledge; guarantee, bail”), equivalent to en- + gage. Cognate with Old English anwedd (“pledge, security”), Old English weddian (“to engage, covenant, undertake”), German wetten (“to bet, wager”), Icelandic veðja (“to wager”). More at wed.
The verb can be used transitively (to engage someone) or intransitively with the preposition 'in' (to engage in an activity).
They engaged to the projectThey engaged in the projectWhen meaning to participate, the verb requires the preposition 'in' before the activity.