Do you know ghouls from goblins and ghosts?
late 14c., ethimolegia "facts of the origin and development of a word," from Old French et(h)imologie (14c., Modern French étymologie), from Latin etymologia, from Greek etymologia, properly "study of the true sense (of a word)," from etymon "true sense" (neuter of etymos "true, real, actual," related to eteos "true") + -logia "study of, a speaking of" (see -logy).
In classical times, of meanings; later, of histories. Latinized by Cicero as veriloquium. As a branch of linguistic science, from 1640s. Related: Etymological; etymologically.
the history of a word or word element, including its origins and derivation. Although the etymologizing of proper names appears in the Old Testament and Plato dealt with etymology in his dialogue Cratylus, lack of knowledge of other languages and of the historical developments that languages undergo prevented ancient writers from arriving at the proper etymologies of words