nostalgia
nuh-STAL-juhnounMeaning a fond, wistful longing for the past
Memory hook NOST-ALGIA: a sweet ACHE for the past. Granny Mae turns the pages of her old photo album and smiles at her first bicycle and her childhood dog; the sweet ache she feels is nostalgia.
The smell of popcorn filled Grandpa with nostalgia for the movie theater of his childhood.
In context Paging through the old photo album, Mom felt a wave of nostalgia: the treehouse, the bicycle with streamers, the summer evenings that seemed to last forever.
Similar wistfulness, longing, homesickness, reminiscence
From Greek nostos (a return home) + algos (pain): it first named homesickness.