submarine (adj.) Look up submarine at Dictionary.com
1640s, from sub- + marine (adj.).
submarine (n.) Look up submarine at Dictionary.com
"submarine boat," 1899, from submarine (adj.). Earlier "a creature living under the sea" (1703). The short form sub is first recorded 1917. As a type of sandwich from 1955, so called from the shape of the roll. Related: Submariner.