Nostalgia today is associated with warm memories and happy recollections, but it used to have a much harsher meaning. When the word was first brought into 1770, it described an intense ache to return home. The etymology of nostalgia (which was first coined by a Swiss student in 1688) reflects that earlier definition. Nost-, the initial part of the word, comes from Ancient Greek nostos, meaning "homecoming", and -algia is from Greek algos, "pain". Nostos comes from a Proto-Indo-European word, nes, with the same denotation; -tos is just an adjectival suffix here. Algos, meanwhile, developed from the verb algein, which meant "to feel pain" and has an uncertain etymology. Usage of the word nostalgia rapidly took off in the twentieth century and peaked in the 1990s.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd