A follicle is a tiny pocket or cavity in your body, usually in your skin, where something grows. Most commonly, we talk about hair follicles, the small tube-shaped structures beneath your skin's surface where each strand of hair grows. You have about 100,000 hair follicles on your scalp alone, and each one acts like a factory producing a single hair.

Think of a hair follicle like a tunnel in the ground where a plant grows up through the soil. The root of your hair sits deep in the follicle, getting nutrients from blood vessels, while the visible hair shaft pushes up and out through the opening. When a hair falls out, the follicle usually starts growing a new one, which is why you don't go bald every time you lose a few hairs.

Your body has other types of follicles too. For example, in biology class you might learn about follicles in the ovaries, which are structures that help egg cells develop. While these serve completely different purposes than hair follicles, they share the basic idea of being small pockets where something important develops and grows.