- the hollow under the arm at the shoulder; axilla.
- the small depression beneath the arm where it joins the shoulderTechnical name: axilla Related adjective: axillary
- slang an extremely unpleasant placethe armpit of the Mediterranean
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.
- The hollow under the upper part of the arm below the shoulder joint, bounded by the pectoralis major, the latissimus dorsi, the anterior serratus muscles, and the humerus, and containing the axillary artery and vein, the infraclavicular part of the brachial plexus, lymph nodes and vessels, and areolar tissue.axilla axillary fossa