Meaning

noun insects having usually a single pair of functional wings (anterior pair) with the posterior pair reduced to small knobbed structures and mouth parts adapted for sucking or lapping or piercing

originPIE word *dwóh₁ Immediately from translingual Diptera + -an, for denoting taxonomic specification, as opposed to instances where "fly" is used informally. From Ancient Greek δίπτερος (dípteros, “two-winged”) + -an, from δι- (di-, “two, di-”) + πτερόν (pterón, “feather, wing”) + -ος (-os, “adjectival suffix”).

Etymology from Wiktionary, CC BY-SA 3.0