The word "aboard" originates from the phrase "on board," meaning on a ship, boat, or other transportation. It is used to describe someone or something as being inside or on a vehicle, vessel, or aircraft. Synonyms for this term include "on," "within," "inside," and "inclusive of." Other synonyms for "aboard" can include "embarked," "en route," "on the move," "on the go," and "traveling." When used in a military context, "aboard" can mean being assigned to a specific ship or aircraft. Overall, there are many ways to describe being "aboard," with different terms that can be used depending on the context and situation.