auld lang syne UK /ˌɔːld læŋ ˈsaɪn/US /ˌɔl(d)læŋ ˈsaɪn/ noun1 •Days gone by; former times.It is in ‘auld lang syne’ that we who are dead find our full despotic kingdom at last—that oneness of sway that even the truest, sweetest love can never assure us of while living. — 1928