Follicle or hair follicle: a structure in the skin that is the growth center and produces a single hair.

Follicular unit: a natural occurring structure in the skin that contains from one to four hair follicles and an oil gland

Follicular unit extraction: a surgical method of removing follicular units from the scalp one unit at a time.

Follicular unit grafting: a surgical method utilizing stereoscopic microscopes to separate follicular units from the skin for use in hair transplantation. It is the gold standard in hair transplantation today.

Graft: a general term in hair transplant surgery to describe a small piece of skin containing hair follicles; it may contain a single hair follicle, a single follicular unit (1-4 hair follicles), or many follicular units

Mega-session: a hair transplant procedure involving the transplanting of at least 2,000 follicular units during one surgery.

Micro-graft: a graft containing one hair follicle

Mini-graft: a graft containing many follicular units; not cut with the use of a microscope these may result in a much less natural appearance