Most movies utilize music in one way or another, but movies in the musical genre elevate music to a very prominent level, sometimes so much so that the movie is all about the music. It's a version of theatrical entertainment that has always been popular on the stage, and it made its way onto the movie screen in the earliest days of cinematic history.
Many movie musicals are based on successful stage musicals that have already proven themselves on Broadway, while others are original stories that emulate the format of the Broadway musical using new songs and plot lines. A subgenre is the dance movie, a form that showcases the moves of the performers more than it focuses on the sound of the music.
In recent years, the animated musical has been one of the most commercially successful of all movie genres. These films duplicate the structure of a stage musical, with a soundtrack full of songs that prop up the storyline and help to develop the characters, but instead of live action actors, the films use animated characters and settings. Disney Studios has long been the master of the animated musical; Snow White and the Seven Dwarfs set the standard back in 1937, and Frozen raised the bar for the genre's commercial success in 2013.