Follicle (noun)

1. A small, hollow, spherical or oblong structure, such as a gland or hair follicle, that contains or produces something, especially a cell or cells.
2. A small sac or cavity containing a glandular secretion or a developing organism, such as a hair or ovum.

Origin:

From latin folliculus, diminutive of follis ("bellows"), from proto-indo-european *bhel- ("to blow"). it means "a small, hollow, spherical or oblong structure, such as a gland or hair follicle, that contains or produces something, especially a cell or cells".

Examples:

1. Each hair grows out of a follicle in the skin.
2. The oil glands are located near the base of the hair follicles.
3. Follicles are the structures in the skin that produce hair.
4. The eggs develop in the ovary's follicles.
5. The follicle of a hair is the small sac from which the hair grows.