Spider silk is a protein fiber spun by spiders.

Extrusion of protein fibers in an aqueous environment is known as "wet-spinning".

When used in feed for livestock or horses, it can be a good source of protein, fiber, and phosphorus, along with various other nutrients.

Silk is a natural protein fiber that can be woven into textiles.

The protein fibers are used as thread that is spun into yarn.

Silk is a "natural" protein fiber, some forms of which can be woven into textiles.

These protein fibers give the dermis its properties of strength, extensibility, and elasticity.

"But hair and nails are both protein fibers."

Funny how we all put so much importance on that non-essential protein fiber; women, anyway.