Definition of Jay 1. United States diplomat and jurist who negotiated peace treaties with Britain and served as the first chief justice of the United States Supreme Court (1745-1829) Noun 2. Crested largely blue bird Noun Synonyms for word "jay" Semanticaly linked words with "jay" Hyponims for word "jay" has derived form jy etymology deejay etymology jaybird etymology jaylike etymologically related gay etymological origin of jay is derived from California jay is derived from Canada jay is derived from Florida jay is derived from Grammatoptila is derived from as is derived from blue jay is derived from bluejay is derived from deejay is derived from green jay is derived from jay thrush is derived from jaycee is derived from jays is derived from jaywalker