ahoy

Used to hail a ship, a boat or a person, or to attract attention.

While he was thus occupied, a voice, still more uncouth than the former, bawled aloud, ‘Ho! the house, a-hoy!’

I made a speaking trumpet of my hands and commenced to whoop “Ahoy!” and “Hello!” at the top of my lungs. […] The Colonel woke up, and, after asking what in brimstone was the matter, opened his mouth and roared “Hi!” and “Hello!” like the bull of Bashan.

Warning of something approaching or impending.

Lawsuits, ahoy! […] Towns can regulate use of their beaches. But what about the waters offshore?

Catalytic converters ahoy – Zeppelin's latest is one of those high-rev 3D driving games that simulates racing tracks from all over the world.

To hail with a cry of "ahoy".

An utterance of this interjection.

There were many ahoys heard from the approaching ship.