From Longman Dictionary of Contemporary Englishbygoneby‧gone /ˈbaɪɡɒn $ -ɡɒːn/ adjective → bygone age/era/days etc
Examples from the Corpus
bygone• It is a relic of a bygone age, a cultural icon with a colorful political past.• He had impeccable manners that somehow always reminded you of an older, bygone age.• On the second floor, room 30 is the favourite: devoted to dolls, toys and other mementos of bygone childhood.• In bygone days the Arms Park had an almost mystical quality for them.• I live part of my time in an imaginary bygone era.• Miss Piggy, Kermit and the rest now come across as symbols of a bygone era.• Since the reprise of coach John Robinson, who brought national championships in a different, bygone era.• Carmarthen's street scenes reflect bygone years as do its placenames. 