bygone UK /ˈbaɪɡɒn/US /ˈbaɪɡɔn/noun 2adjective 1forms 1 noun[usually plural]2 •An event that happened in the past. •An object from the past; a relic, antique, etc. adjective1 •Having been or happened in the distant past.Near by he could see the thicket of raspberry canes, growing tall and close like a tropical jungle, in whose shadow he had played with the Boy on bygone mornings. — 1922 formsbygones