- Follicular unit
- The natural grouping in which hair grows on the scalp — usually one to four hairs emerging together from a shared opening. Transplants move these units intact rather than individual hairs.
- Donor area
- The band of hair at the back and sides of the head whose follicles are largely resistant to the hormonal process driving pattern hair loss. It is the only source of transplantable hair, and it is finite.
- Recipient area
- The bald or thinning zone where grafts are placed.
- Graft
- A single follicular unit prepared for transplantation. A graft may contain one, two, three or four hairs, which is why graft counts and hair counts are not the same number.
- Miniaturisation
- The process by which affected follicles produce progressively finer, shorter, less pigmented hairs before ceasing altogether. Visible under magnification and the key sign that a follicle is still alive.
- Norwood scale
- A seven-stage classification of male pattern hair loss used to describe the pattern and communicate about it consistently between doctors.
- Shock loss
- Temporary shedding of existing hair around a surgical site after a transplant. Usually recovers over months.
- Shedding phase
- The expected fall of transplanted hair shafts in roughly weeks two to eight after surgery, while the follicle remains in place and enters a resting phase.
- Hairline design
- The drawing agreed before surgery that determines the position, shape, asymmetry and softness of the new hairline. The single most consequential decision in the procedure.
- Density
- Hairs or follicular units per square centimetre. Native scalp density cannot be reproduced by redistribution; achievable transplant density is lower and can still read as full coverage.
- Donor reserve
- The hair remaining in the donor area after previous sessions — the resource available for hair loss that has not yet happened.
- Follicular unit extraction
- Harvesting grafts individually with a small punch, leaving many small round marks rather than a linear scar.
- Strip harvesting
- Removing a thin band of donor scalp and dissecting it into grafts under magnification, leaving one fine linear scar.
- Direct implantation
- A placement method in which an implanter creates the recipient site and places the graft in one movement.
- Scalp micropigmentation
- Tattooed pigment dots that mimic short shaved hair, used to reduce the contrast between scalp and hair. Not a hair restoration, but a genuine option where donor supply is inadequate.