What does armpit mean?
The armpit is the hollow area at the underside of the shoulder where the arm meets the torso, known in anatomy as the axilla. It is a warm, enclosed region of skin rich in sweat glands and hair follicles, which makes it central to everyday concerns about perspiration and body odor — hence its constant presence in the marketing of deodorants and antiperspirants. In ordinary usage the word is informal but perfectly standard, covering both the physical region ('she carried her bag under her armpit') and related practical matters such as shaving or clothing stains. It also carries a well-established figurative sense: calling a town or district 'the armpit' of a country or state humorously labels it as unpleasant or unglamorous, as in the popular jibe 'the armpit of America.' Though humble in subject matter, the word is vivid, widely understood across English-speaking regions, and useful precisely because it names a body part that more clinical vocabulary leaves inaccessible to casual conversation.
The hollow area on the underside of the shoulder where the arm joins the body; the axilla.
"The shirt was cut loosely so it wouldn't chafe at the armpits."
Plural 'armpits'; informal register, with 'axilla' preferred in clinical writing.
(Figurative) A place considered unpleasant, dirty, or undesirable.
"Critics dismissed the seaside resort as the armpit of the coast."
Always figurative and mildly disparaging, typically used for comic effect.
Regular plural; used when referring to both sides of the body or multiple people.
"Both armpits of his favorite T-shirt were stained with sweat."
New Jersey has been jokingly nicknamed 'the armpit of America' — a backhanded compliment no state ever asked for.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of armpit
Armpit is a straightforward compound of two Old English words: 'arm,' which descends from Proto-Germanic roots related to the Indo-European base *ar- denoting fitting or joining (a root also seen in Greek harmos, 'joint,' whence 'harmony'), and 'pit,' from Old English pytt, borrowed ultimately from Latin puteus, 'well or pit.' The compound arose naturally in Middle or early Modern English to name this bodily hollow. Its Germanic cousins preserve the same logic: German has Achselhöhle ('armpit hollow'), reflecting the shared root behind 'axilla'-related terminology rather than a direct borrowing.
How armpit is actually used
The word is neutral in everyday speech but informal in register; in medical or clinical contexts, 'axilla' (plural 'axillae') is preferred. The figurative sense describing an unappealing place is mildly derogatory and usually humorous or hyperbolic.