chitin

Everyday

(science) Chitin is the tough natural material that makes up the hard outer skeleton of insects, spiders, crabs and lobsters, and the cell walls of fungi. tree →

In the lessons

In science lessons on invertebrates pupils learn that insects have an exoskeleton made of chitin instead of bones inside. Animals with chitin shells must moult (shed them) to grow. It is used in the exam voice and science books.

Examples

• A beetle's hard shell is made of chitin. tree →
• Crabs have chitin in their shells. tree →
• Chitin protects insects like a suit of armour. tree →
• Mushrooms have chitin in their cell walls. tree →
• The cicada left its chitin shell on the tree. tree →
• Because chitin cannot stretch, insects must moult to grow. tree →

Note

Pronounced «KY-tin». Uncountable. Chitin is not bone; it is outside the body.