Aboard/əˈbɔːrd/ Definition 1 of 3Pro Tip 1/3Transportation Context Used when someone is getting on transportation or already inside it. She stepped aboard the airplane just in time. Pro Tip 2/3Embarking Journey 'Aboard' implies beginning a journey or travel. The passengers were aboard and ready for departure. Pro Tip 3/3Welcome Gesture Often used to welcome someone onto transportation or into a group. The captain welcomed everyone aboard.