stridor
Concise Oxford English Dictionary © 2008 Oxford University Press:
stridor /ˈstrʌɪdə/
▶noun a strident sound.
■ Medicine a harsh vibrating noise when breathing, caused by obstruction of the windpipe or larynx.
– origin C17: from L., from stridere ‘to creak’.
'stridor' also found in these Oxford entries:

