A description given to the Bristol based musical group Portishead* by musical journalists, due to their melancholy sound.
This term is extremely general, and many musical groups and artists could fit this description. However I have not heard of many described in this way; Cat Power and Mandalay have been called sadcore.
Personally I don't like this label, and don't feel it captures Portishead at all. Their music may have a melancholy sound, but this description doesn't represent the entity that is Portishead. If I would use any label to describe the band it would be Trip Hop, but why go further than labeling their sound 'Portishead'. I feel that is the perfect description. After all it's the music that matters, not the label.
*Portishead are more commonly labeled Trip Hop. Although it should be known that they themselves aren't fond of any label. They see the music as being far more important than any word used to describe it.