Around 70% of the earth's surface (5)

I believe the answer is:

ocean

(Other definitions for ocean that I've seen before include "Large expanse of sea" , "Pacific, for example" , "Extensive sea area" , "Huge sea" , "Salt water expanse" .)

I've seen this clue in The New York Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.