Hiraeth
Etymology
A Welsh word often called untranslatable. Its roots are debated; it braids together longing, grief, and a sense of a lost homeland. As with several such words, "untranslatable" is partly a cultural claim — but English genuinely lacks a single equivalent.
noun · /HEER-ithe/
A deep longing for a home you can’t return to — or one that may never have existed.
What it names
Homesickness for a place, time, or version of life that is gone or imagined — heavier and more spiritual than ordinary nostalgia.
Example
Scrolling old photos of a childhood town long since redeveloped, she felt a wave of hiraeth.
Related idea
Saudade aches for an absent something; hiraeth aches specifically for home. Both resist translation.