nostalgia

2. A feeling of sadness mixed with pleasure when thinking about happy times that are gone.

There was a touch of nostalgia in his voice as he described the old neighborhood.

3. A sentimental longing for a place or time you once knew.

The smell of fresh bread gave him nostalgia for his grandmother's kitchen.

4. In medicine, a former term for severe homesickness treated as an illness.

In the 1800s, doctors diagnosed soldiers with nostalgia when they pined for home.