According to Wikipedia
… nostalgia describes a yearning for the past, often in idealized form. [A Greek word] consisting of nóstos, meaning “homecoming” and álgos, meaning “pain, ache”. It was described as a medical condition, a form of melancholy, during the 18th century …
A more direct translation would be homesickness. It’s an interesting concept that seems is something almost everyone has in common. Across cultures and across age groups. It’s universal. This is why I think it’s such an effective tool to use for making communication that speaks to the emotions.