ship of the line
noun
1.
a former sailing warship armed powerfully enough to serve in the line of battle, usually having cannons ranged along two or more decks; battleship.
Origin
1700-10
Examples from the web for
ship of the line
It will require a
ship of the line
, a frigate, and some good sloops to keep.
British Dictionary definitions for
ship of the line
ship of the line
noun
1.
(
nautical
) (formerly) a warship large enough to fight in the first line of battle