The branch of lexicology that studies the origins and history of proper names

WordNet Word definitions in WordNet
n. the branch of lexicology that studies the forms and origins of proper names

Wiktionary Word definitions in Wiktionary
n. The branch of lexicology devoted to the study of names and naming, especially the origins of names.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"scientific study of names and naming," 1936, from onomastic ; also see -ics .

Wikipedia Word definitions in Wikipedia
Onomastics or onomatology is the study of the origin, history, and use of proper names . Onomastics originates from the Greek ὀνομαστικός ( onomastikós ), which translates to "of or belonging to naming", from ὄνομα ( ónoma ) meaning "name". Toponymy or ...