Melancholy is a state of deep sadness or sorrow, often without a clear cause. It can be characterized by feelings of gloom, introspection, and a sense of longing. This emotional state has been explored in various forms of art and literature, reflecting the human experience of loss and reflection. Historically, melancholy was associated with the four humors in ancient medicine, where it was linked to an excess of black bile. In modern psychology, it can be related to conditions such as depression, though it can also be a temporary emotional response to life events or changes.