Definitions

1. preposition

on, in, or on board of (a ship, aircraft, vehicle, or other means of transport)

“They boarded the plane and took off.”

2. verb

to get on or into (a ship, aircraft, vehicle, or other means of transport)

“She boarded the bus and found a seat.”

3. adverb

in or on board of (a ship, aircraft, vehicle, or other means of transport)

“They were aboard the ship for several days.”