Nostalgia is a sentimental longing or wistful affection for the past.

The ancient Greek word nostimon is an etymological ancestor of nostalgia. It was first used in Homer’s Odyssey in which Odysseus tells us: “But I desire and I long every day to go home and to look upon the day of my return.” Odysseus experiences profound homesickness for Greece and longs for his “day of return” — or nostimon emar.

In the late 1600s, Swiss medical student Johannes Hofer noticed a pattern in his patients who were living far from home. Those who were obsessed with returning to their estranged locations became physically, sometimes fatally, sick. Symptoms included bouts of weeping, palpitations, insomnia, slow fever, and anorexia. To reflect this phenomena, he coined the medical term “nostalgia” in 1688, which he created by combining the Greek words nostos (homecoming) and alga (pain).

By the 19th century, nostalgia was regarded as a psychiatric disorder, namely a form of melancholia and depression.

Today, nostalgia sheds its medical connotations and expands upon its original meaning of homesickness. It is widely regarded to have taken on a more positive meaning, expanding beyond homesickness to include a sentimental longing for past people, places, events, or various objects.