What does comedo mean?
A comedo (plural: comedones or comedos) is a clogged hair follicle in the skin, packed with sebum, dead skin cells, and sometimes bacteria. It is the fundamental lesion of acne vulgaris and takes two familiar forms: when the follicle's opening stays open, the contents oxidize and darken, producing a blackhead (an open comedo); when the pore remains closed, it forms a flesh-colored bump known as a whitehead (a closed comedo). The word comes from the Latin comedere, meaning 'to eat up' or 'devour', reflecting the early impression that such blemishes appeared to consume the flesh. Comedo is primarily a medical and dermatological term, encountered in clinical literature, product labeling, and professional skincare contexts; ordinary conversation favors the simpler terms blackhead and whitehead. Its derivatives, such as comedogenic (tending to cause blocked pores), are common in cosmetics marketing.
nounA clogged hair follicle in the skin filled with sebum and dead skin cells; the primary lesion of acne, occurring as an open comedo (blackhead) or a closed comedo (whitehead).
- A clogged hair follicle filled with sebum and keratin, appearing as a blackhead (open comedo) or whitehead (closed comedo); the characteristic primary lesion of acne vulgaris.
"The dermatologist gently extracted several comedones during the patient's facial treatment."
"Salicylic acid helps dissolve the debris inside an open comedo."
"Histological examination of the biopsy revealed numerous closed comedones beneath the skin's surface."
Medical writing conventionally uses the Latin plural 'comedones'; the anglicized 'comedos' also occurs but is less formal.
"The patient's forehead was covered with dozens of small closed comedones."
The humble blackhead has a name that literally means 'devourer' — dermatologists borrowed it from Latin because these tiny plugs seem to eat their way into the skin.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does comedo come from?
The word comedo derives directly from the Latin verb comedere, formed from com- (an intensive prefix) plus edere ('to eat'), giving the sense 'to eat up' or 'devour'. It entered English medical usage around the late 18th century, when physicians adopted it to describe skin blemishes that seemed to gnaw at or consume the tissue. The same Latin root edere underlies related English words such as edible and comestible. In modern dermatology the Latin plural comedones is standard, alongside derived forms like comedogenic and comedolytic.
Related word forms
How comedo is actually used
A clinical and technical term used chiefly by dermatologists and skincare professionals rather than in everyday speech; lay speakers typically say 'blackhead' or 'whitehead'. The Latin plural 'comedones' is preferred in medical writing over the anglicized 'comedos'.
Easily confused with comedo
A comedown is a decline or loss of status (or the aftermath of a drug's effects), while a comedo is a clogged skin pore associated with acne.