Origin and history of tracheoscopy

word-forming element meaning "viewing, examining, observing," from Modern Latin -scopium, from Greek -skopion, from skopein "to look at, examine" (from PIE root *spek- "to observe").

before vowels trach-, word-forming element used from early 19c. in anatomy, biology, etc., "of or pertaining to the trachea, having the form of a trachea, of the trachea and," from Latinized form of Greek trakheia, as used in anatomy in reference to the windpipe (see trachea). Greek trakheia is from trakhys "rough, uneven, stony," figuratively "severe, harsh," also used of rough voices, anger, etc., which according to Watkins is connected to the root of dark and dreg, but Beekes discounts this and says it is related to thrassein "to trouble, disturb."

English also uses trachy- in a few words to indicate "rough."