I. ˈən-dər-ˈärm adjective
Date: 1816
1. : underhand 4
2. : placed under or on the underside of the arm
underarm seams
II. ˌən-dər-ˈärm adverb
Date: circa 1909
: underhand
III. ˈən-dər-ˌärm noun
Date: 1923
1. : armpit 1
2. : the part of a garment that covers the underside of the arm