This article discusses the contribution of cognitive linguistics to diachronic lexicology and describes how lexical studies within cognitive linguistics are gradually and naturally evolving toward a sociolexicological approach that links up with sociolinguistics. It takes the distinction between semasiology and onomasiology as its basic organizing principle. Based on this distinction, the article charts the field of onomasiology (probably the lesser known of the two subfields of lexicology) and examines the contribution of cognitive linguistics to that field. It also illustrates the importance of sociolexicology for the study of onomasiological variation and change, with references to sociolinguistic studies at large within cognitive lingui...