ocean noun definition in Coastlines and the sea topic from the Oxford Advanced Learner's Dictionary

ocean

 noun: Coastlines and the sea topic
(also the ocean) [singular] (especially North American English) the mass of salt water that covers most of the earth’s surface the depths of the ocean People were swimming in the ocean despite the hurricane warning. The plane hit the ocean several miles offshore. Our beach house is just a couple of miles from the ocean. an ocean liner Ocean levels are rising.