Learner's definition of ABOARD
: on, onto, or within a train, a ship, an airplane, etc.上（火车、船、飞机等），在（火车、船、飞机等）上 ◊ All aboard! is a call for passengers to get onto a ship or train because it is ready to leave.（船或火车即将出发时对乘客的提醒）请上船（请上车）！
2 aboard /əˈboɚd/ preposition
2 aboard
/əˈboɚd/
preposition
Learner's definition of ABOARD
: on or into (a train, ship, etc.)在（火车、船等）上