"act of listening," 1630s, from Latin auscultationem (nominative auscultatio), noun of action from past-participle stem of auscultare "listen attentively to" (see auscultate). Medical sense is from 1821, "a listening to the internal parts of the body via a stethoscope."
aurora
aurora borealis
auroral
*aus-
auscultate
auscultation
auspex
auspices
auspicious
Aussie
auster