board
‘board’
If you board a bus, train, plane, or ship, you get on it or into it.
Gerry took a taxi to the station and boarded a train there.
I boarded the plane for San Diego.
‘on board’
When you are on board a bus, train, plane, or ship, you are on it or in it.
There were 13 Britons on board the plane.
The crash killed all 57 passengers on board.
Be careful
Don't use ‘of’ after on board. Don't say, for example, ‘There were 13 Britons on board of the plane’.
Don't use ‘of’ after on board. Don't say, for example, ‘There were 13 Britons on board of the plane’.