u-boats

noun

1. a German submarine.

noun

1. a German submarine, esp in World Wars I and II

1916 (said to have been in use from 1913), partial translation of German U-Boot, short for Unterseeboot, literally “undersea boat.” German submarines during World War I and World War II. U-boat is a translation of the German U-boot, which is short for Unterseeboot, or “undersea boat.”