In the middle of the nineties, in the UK, US hip hop had taken hold and dancefloor DJs used to playing house and electronica changed their styles by adopting the beats of hip hop into electronic / dub style music.
This music was layered with slow beats with a laid back groove and often had jazz and funk samples embedded within. Some of the most famous artists making so-called trip hop music were Massive Attack, Portishead and Coldcut. Mo-Wax, the Uk label that released mostly trip-hop became very popular in the 90s and was responsible for breaking many new and experimental artists.
Over the years a few famous pop artists have adopted the style, including Radiohead, Rihanna and Nine Inch Nails.
The term trip-hop is sometimes used in a derogatory way to describe music that was often quite dark and sometimes completely unrecognizable from its origins of hip hop.
Kool Keith, the infamous stream of consciousness rapper famously declares on one of his records “there is no such thing as trip hop”. Its an understandable point because many of the underground rappers would freestyle over beats and loops that some might refer to today as trip hop, while to the insiders it was simply a clever chilled out hip hop beat.
Musicians tend to hate genres as they only seem to simplify musical styles which develop over time and are a continuum rather than simply rebranded styles used as an aid to selling.