1. a tough, protective polysaccharide substance that forms the outer skeleton of insects, crustaceans, and other arthropods, and is also found in fungi.
Usage: uncountable noun; scientific/biological term

Examples

• The exoskeleton of beetles is made primarily of chitin.
• Chitin provides structural support and protection for insects and crustaceans.
• Lobster shells contain chitin, which makes them hard and durable.
• Scientists are studying chitin as a potential sustainable material for industrial applications.
• The wings of dragonflies are reinforced with chitin.
• Fungi cell walls contain chitin, unlike plant cell walls which contain cellulose.