To get on or into (a ship, aircraft, or other vehicle). Passengers began to board the plane for their flight to New York.
To provide someone with regular meals and lodging in exchange for payment. The family agreed to board the student for the duration of the school year.
To cover or close with boards. They decided to board up the windows before the storm hit.
To take meals or lodging for payment at someone else's house or an institution (intransitive). During university, he boarded with an elderly couple near campus.