chitin

As a noun chitin

is chitin.

As an adjective chitinlike is

resembling chitin or some aspect of it.

As nouns the difference between chitin and chitosan

is that chitin is a complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans while chitosan is a carbohydrate oligosaccharide derived from chitin, sometimes used to the absorption of fat.

As nouns the difference between chitin and chitooligosaccharide

is that chitin is chitin while chitooligosaccharide is (organic chemistry) an oligosaccharide derived from chitin; chitosan.

As nouns the difference between chitin and chitooligomer

is that chitin is chitin while chitooligomer is (organic chemistry) a class of carbohydrate oligomer derived from chitin; chitooligosaccharide.