1. the hollow under the arm where it is joined to the shoulder; - Example: "they were up to their armpits in water" [syn: armpit, axilla, axillary cavity, axillary fossa]
WordNet (r) 3.0 (2006):
axillary fossa
n 1: the hollow under the arm where it is joined to the
shoulder; "they were up to their armpits in water" [syn:
armpit, axilla, axillary cavity, axillary fossa]