OST

OST is an acronym standing for "Original Sound Track" usually used to refers to all the music that is heard in an anime or the officially released set of music (usually CD, BD/DVD, or online). Music on an OST can be primarily be instrumental tracks, but can also include character songs, cover songs, insert songs, licensed songs, OP or ED tracks (full-length or TV-sized &mdash around 1 min 30 sec or less).