cymoscope

First attested as cymatoscope in 1903 and as cymoscope in 1905; formed as cȳm- (the short stem of the Latin cȳma, from the Ancient Greek κῦμα (kûma), kūma, “wave”) + -o- +‎ -scope. Cymatoscope is philologically prescribed in place of cymoscope because it preserves the long stem (κῡμᾰτ- (kūmăt-), kūmat-) of its ultimate Ancient Greek etymon, which properly does not form compounds on its short stem (κῡμ- (kūm-), kūm-).