OST is the abbreviation of Original Sound Track, which literally means soundtrack (movie soundtrack album), that is, the soundtrack with background music (or songs) stored in all the soundtracks of the movie. Because it is a term in movies, it is also called movie soundtrack or movie soundtrack. OST generally refers to the soundtrack or song in the movie. The most common media for this kind of music distribution are CDs and tapes, but there are also some SACD. Its content can include opening song, ending song, episode, background music, role song and so on.

BGM=Background Music, which means background music in English, refers to the music used as background in movies, TV plays and other film and television works, usually silent. The real BGM originated from European opera, and developed rapidly from the audiovisual film. That's what BGM means, and it often appears in the animation industry. It is generally believed that BGM is an indispensable and important element in animation. It not only needs to cooperate with the plot development of the picture, but also has its own unique style, which is the lubricant and propeller of animation. Because of its importance, almost every animation will extract its own BGM, which will be included in the corresponding soundtrack ost and sold as a by-product.