indie
Indie is short for independent. Popularly used as a short term for "indie rock", although this is meant to be inaccurate.

Some people are unaware that indie rock is just rock music whose artists are on an independent (or indie) record label.

Indie is not a genre of music. It can be hip hop on an independent record label. The latter is a record label which operates without funding by major record labels.

There are also indie films, indie art, etc., which are films/art/etc which are independent from commercial, mainstream establishments (just like indie music).
dizzee rascal, rebecca black, fleet foxes and arcade fire are all indie artists. they are on independent record labels.