Keratin (noun)

Keratin is a fibrous protein that is the main structural component of hair, nails, feathers, hooves, and horns.

Origin:

The word keratin is derived from the greek word "keras" meaning "horn".

Examples:

1. Hair is made up of a protein called keratin.
2. Nails are made of a protein called keratin.
3. Keratin is a fibrous protein that is the main structural component of hair, nails, feathers, hooves, and horns.
4. Keratin is a strong, durable protein that gives strength and rigidity to hair, nails, and other body structures.
5. Keratin is a protein that is also found in the outer layer of the skin, which helps to protect it from damage.