A movie studio, or film studio, is a place where movies are made. A movie studio can be an area where the movie is filmed; like an indoor (interior) stage or room, or an outdoor area in which only those making the movie are allowed to be.
The term movie studio also means a production company because these companies often had - in the 1920s to the 1940s - their own studios in their own buildings. Even though most production companies do not now have their own studios, the term is still used in this way.
Movie studio Facts for Kids. Kiddle Encyclopedia.