What is the meaning of Aboard?

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

On or onto a horse, a camel, etc.

On base.

Into a team, group, or company.

Alongside.

On board of; onto or into a ship, boat, train, plane.

Onto a horse.

Across; athwart; alongside.

Source: wiktionary.org