Definition of full house
A full house is a full hand. It's also called a full house. A full house is a pair plus three of a kind. If you have AK on A-K-A, you have a full house or boat. Full hand, full house, full, boat, full boat, are all synonyms for the same hand. At casino poker tables, you'll hear all expressions with equal frequency. Players who want to show other players that they weren't born yesterday will use "boat" more often than full hand or full house. The expression gives the impression that you're more erudite than the other players, that you know the game better.
Poker is all about marine analogies
Boat isn't the only term referring to marine vocabulary. We speak of the turn, the river, a float (when we call a bet with the intention of bluffing on a future street), etc. There are also Wild West analogies (a barrel is called a shot when you bet, pre-flop kings are called cowboys, etc.). On the other hand, at the poker table, it's always best not to flaunt our knowledge too much to the other players, so as not to arouse their suspicion of our skills!
