sigmoidoscopy

Etymology tree
Ancient Greek σῖγμᾰ (sîgmă)
Ancient Greek -ο- (-o-)
Proto-Indo-European *weyd-
Proto-Indo-European *-os
Proto-Indo-European *wéydos
Proto-Hellenic *wéidos
Ancient Greek εἶδος (eîdos)
Proto-Indo-European *-os
Proto-Indo-European *-ēs
Ancient Greek -ης (-ēs)
Ancient Greek -ειδής (-eidḗs)
Ancient Greek σῑγμοειδής (sīgmoeidḗs)bor.
English sigmoid
Ancient Greek -ο- (-o-)der.
Latin -o-bor.
English -o-
Proto-Indo-European *speḱ-
Proto-Indo-European *-yeti
Proto-Indo-European *spéḱyeti
Proto-Hellenic *sképťomai
Ancient Greek σκέπτομαι (sképtomai)
Proto-Indo-European *-ós
Proto-Hellenic *-ós
▲
Ancient Greek -ος (-os)influ.
Ancient Greek -ός (-ós)
Ancient Greek σκοπός (skopós)
Proto-Indo-European *-eti
Proto-Indo-European *-eyéti
Proto-Indo-European *-esyéti
Proto-Indo-European *-éh₁ti
Proto-Indo-European *-yeti
Proto-Indo-European *-éh₁yeti
Proto-Indo-European *-yeti
Proto-Indo-European *-éyeti
Ancient Greek -έω (-éō)
Ancient Greek σκοπέω (skopéō)der.
English -scopy
English sigmoidoscopy
From sigmoid + -o- + -scopy.