Yes, it is one word "aboard" -- as an adverb or preposition, it means "on board" a vehicle such as a bus, train, plane, or ship.
One of my projects is aboard the Skylab.
No, the word 'aboard' is an adverb, a word that modifies a verb, an adjective, or another adverb and a preposition, a word that connects a noun or noun phrase to another word in the sentence.EXAMPLESadverb: We came aboard with a high expectations.preposition: We were greeted graciously when we came aboard the ship.
The Captain said to me, "climb aboard, Son!"
at home
The root word in "aboard" is "board," which refers to a piece of wood or other material used for a specific purpose, such as a floor or platform.
As soon as the crew were ready, they let the passengers come aboard the ship.
The ship was leaving soon so people said to hurry up and get aboard
aboard
Embark
aboard
aboard.
Off the truck