Nostalgia is a sentimentality for the past, typically for a period or place with happy personal associations. It is an emotion that can be triggered by something reminding an individual of an event or item from their past, and the resulting emotion can vary from happiness to sorrow. The term "feeling nostalgic" is more commonly used to describe pleasurable emotions associated with and/or a longing to go back to a particular period of time.

Nostalgia serves as a coping mechanism and helps people to feel better about themselves. It makes people more willing to engage in growth-oriented behaviors and encourages them to view themselves as growth-oriented people. Additionally, nostalgic people have greater perceived meaning, search for meaning less, and can better buffer existential threat.

Consumers can feel nostalgic for something they have never experienced due to efficient advertising schemes, a phenomenon referred to as vicarious nostalgia.

In summary, nostalgic means feeling or inspiring nostalgia, which is a longing for or thinking fondly of a past time or condition. It is an emotion that can be triggered by something reminding an individual of an event or item from their past, and it can be a positive feeling that makes people feel happy.