Carried or used on or in a vehicle or vessel / (by extension, figuratively) Being a part of, being included in, participating in

On or in a vehicle or vessel; aboard; on board.

(figuratively) To become a part of a group; to incorporate (someone) into a group. / (figuratively) To begin to use a product or service; to take (someone) on as a new customer of a product or service.

(business) The process of bringing a new employee on board, incorporating training and orientation.

plural of onboarding

simple past tense and past participle of onboard

Third-person singular simple present indicative form of onboard