Post-rock

Post-rock is a music genre characterized by nontraditional use of instruments and high musical density. Although firmly rooted in the indie scene, post-rock's elusive and complex style bears little resemblance musically to that of indie rock. However, as post-rock music is often recorded on independent labels, indie and post-rock often share the same level of obscurity.

The term was coined by Simon Reynolds in a review of Bark Psychosis' album Hex, published in the March 1994 issue of Mojo magazine. Reynolds expanded upon the idea later, most notably in an article found in the May 1994 of The Wire. He used the term to describe a sort of music "using rock instrumentation for non-rock purposes, using guitars as facilitators of timbres and textures rather than riffs and power chords."

Originally used to describe the music of such bands as Cul-de-Sac, Stereolab, Laika, Disco Inferno, Moonshake, Seefeel, Bark Psychosis and Pram, it spread out to be frequently used for all sorts of jazz- and Krautrock-influenced, instrumental, electronica-added music made after 1994. Bands from the early 1990s such as Slint, or earlier, such as Talk Talk were influential on this genre.

As with many musical genres, the term is arguably inadequate: it is used for the music of Tortoise as well as that of Mogwai, two bands who have very little in common besides the fact that their music is largely instrumental.

From Wikipedia: Post-rock.