gradual decline or shrinkage of tissue or organ
Atrophy refers to the gradual decline or shrinkage of tissue or an organ due to a reduction in cell size or number. In the context of hair and alopecia, atrophy can involve the thinning of the scalp or hair follicles, leading to hair loss or reduced hair density. This process can be caused by various factors, including aging, hormonal changes, or underlying medical conditions.