three-decker

noun

1. any ship having three decks, tiers, etc.
2. (formerly) one of a class of sailing warships that carried guns on three decks.
3. a sandwich made of three slices of bread interlaid with two layers of filling; club sandwich.
4. something having three layers, levels, or tiers.

noun

1. 1. anything having three levels or layers
   2. (as modifier)a three-decker sandwich
2. a warship with guns on three decks