/ ˌsʌbməˈriːn; NAmE ; ˈsʌbməriːn/ noun , adjective
■ noun (also informal sub )
1.
a ship that can travel underwater :
a nuclear submarine
a submarine base
2.
(also ˌsubmarine ˈsandwich , hero ) (all NAmE ) a long bread roll split open along its length and filled with various types of food
■ adjective
[ only before noun ] ( technical ) existing or located under the sea :
submarine plant life
submarine cables