Glossary of terms used on this site

progressive depigmentation of the hair resulting from melanocyte activity cessation within the hair follicle.

involution phase (regression)  in the hairs’ growing cycle. The hair stops growing. The catagen phase lasts 15 to 20 days.

term that is improperly used to describe the multiplication, in a laboratory, of hairs taken from an individual. It is  more appropriate to describe it as multiplication of follicular cell implants. 
This technique is still experimental .

upper part of the scalp, also referred to as the vertex