What is the big claw on a crab called?

The big claw on a crab is called a chela (/ˈkɪlə/; pl. chelae). Chelae are specialised appendages found in some arthropods, such as crabs, lobsters, and scorpions. They consist of two钳子, one fixed and the other movable, which are used for grasping, crushing, or cutting food, and for defence. Chelae are also sometimes used for locomotion, such as in the case of the ghost crab.