1. Onomasiology is the branch of lexicology that departs from a concept or a referent and asks for the names bestowed to it by different speech communities.
2. The study of names or naming; also, a branch of semantics concerned with related words and their meanings; the study of nomenclature.

Onomasiology is central to human interest in language. Due to the rich quantity of modern linguistic working materials; such as, dialect dictionaries, minutely compiled corpora etc., onomasiological studies can and must investigate small dialect areas in a detailled way in order to gain valuable insights into the processes of naming and name-changing.

Onomasiologists need good bibliographies, encyclopaedias, and some type of coherent linguistic data base to come up with comprehensive results.