Aboard \A*board"\, adv. [Pref. a- on, in + board.]

On board; into or within a ship or boat; hence, into or within a railway car.

2. Alongside; as, close aboard. Naut.:

To fall aboard of, to strike a ship's side; to fall foul of.

To haul the tacks aboard, to set the courses.

To keep the land aboard, to hug the shore.

To lay (a ship) aboard, to place one's own ship close alongside of (a ship) for fighting.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Aboard \A*board"\, prep.

1. On board of; as, to go aboard a ship.

2. Across; athwart. [Obs.]

Nor iron bands aboard The Pontic Sea by their huge navy cast. --Spenser.

Source: Webster's Revised Unabridged Dictionary (1913)