means Feeling a wistful, often sentimental longing for the past — for a time, place, or way of life now gone.

from Coined in the late 1600s by a Swiss medical student, Johannes Hofer, who stitched together two Greek words: nostos, 'homecoming,' and algos, 'pain.' He needed a clinical name for the aching, sometimes deadly homesickness he saw in Swiss mercenaries fighting far from their mountains. So 'nostalgia' began life as a diagnosed disease — literally 'the pain of wanting to go home' — before it softened over the centuries into the gentle, bittersweet longing we mean today, no longer for a place so much as for a vanished time.