turtleback definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
an arched structure built over the deck of a ship as a protection against heavy seas
turtleback definition by American Heritage Dictionary
Something shaped like the back of a turtle, especially:
a. Nautical An arched structure erected over the deck of a ship as protection from heavy seas.
b. Archaeology A stone tool with a convex side.
- turˈtle·backˌ, turˈtle·backedˌ adjective