turtle

Concise Oxford English Dictionary © 2008 Oxford University Press:
turtle/ˈtɜːtl/

▶noun

• 1 a marine or freshwater reptile with a bony or leathery shell and flippers or webbed toes. [Many species in the order Chelonia.]

  ■ the flesh of a sea turtle, used chiefly for soup.

• 2 a directional cursor in a computer graphics system which can be instructed to move around a screen.

– phrases
turn turtle (chiefly of a boat) turn upside down.

– origin C16: appar. an alt. of Fr. tortue (see tortoise).