The hollow beneath the junction regarding the arm and neck the axilla
- the hollow beneath the arm in which its accompanied towards neck
- The hollow under the junction for the arm and neck; the axilla.
mid-14c., from arm (n.1) + pit (n.1). Arm-hole (early 14c.) was used in this sense but was obsolete by 18c. Colloquial armpit of the nation for any locale regarded as ugly and disgusting was in use by 1965.
(letter.) The hollow under the junction associated with the supply and neck; the axilla.