armpit
UK[ˈɑːm.pɪt]US[ˈɑːrm.pɪt]
n
The hollow place under your arm where it joins your body.
Morpheme Breakdown
arm
pit
arm
body part
pit
hollow
Etymology
The word 'armpit' is a transparent compound formed from two Old English roots. 'Arm' has a stable history, referring to the limb from its Proto-Indo-European root h₂er- (to fit together). 'Pit' evolved from a term for a natural or man-made hole in the ground. The compound logic is vividly literal: the body's 'arm' + a 'pit' or hollow, directly describing the anatomical cavity formed where the arm connects to the torso. This straightforward descriptive naming is characteristic of many common English body part terms.
Analysis
Structure: arm (body part) + pit (hollow)
'Arm' originates from Old English 'earm', meaning the upper limb of the body, from Proto-Germanic armaz. 'Pit' originates from Old English 'pytt', meaning a hole or cavity in the ground, from Proto-Germanic putjaz, likely from Latin 'puteus' (well).
Examples
He applied deodorant to his armpit.
The doctor checked the lymph nodes in her armpit.
He was sweating so much that his shirt had dark patches under the armpits.