turtle
n. countablen. a large reptile with a hard shell on its back that it uses for protection. Most types live in the water and come onto land to lay eggs.
n. a large aquatic or land-dwelling reptile of the order Testudines, characterised by a bony or leathery shell developed from their ribs. Often used specifically for sea-dwelling species in British English, while serving as a general term for all chelonians in American English.
The sea turtle swam slowly through the coral reef.
During our vacation to the coast, we watched a turtle crawl across the sand to reach the ocean.
Conservation efforts have focused on protecting the nesting beaches where every turtle must return to deposit its eggs, ensuring the survival of the next generation.
In British English, 'turtle' usually refers to sea-dwelling species, whereas 'tortoise' refers to land-dwelling ones; in American English, 'turtle' is often the general term for both.