At the theatre you can see plays, e.g. Hamlet by Shakespeare, or musicals, e.g. Phantom of the Opera by Andrew Lloyd Webber. In a play the cast (= the total number of actors) is usually quite small, but musicals often have a very large cast.
One difference between the theatre and cinema is that you usually book (= reserve) tickets in advance (= some time before the actual performance) if you are going to the theatre. Another difference is that the audience (= the people watching the play/musical) clap at the end of the performance. This does not usually happen (in Britain) at the end of a film.
Plays are performed on stage, films are shown on screen. In your country, films in English are either shown with subtitles (= there is a translation across the bottom of the screen), or they are dubbed (= the English is removed and replaced by actors speaking in your own language).
Films are set (= take place) in many different periods and places, e.g. Room with a View is set in the early part of the 20th century; Blade Runner is set in the future. And when people talk about films, they often talk about the director, e.g. Spielberg, Bertolucci; and the stars, the most important actors and actresses, e.g. Tom Hanks and Jodie Foster.
Types of film
Describing plays and films
Journalists write articles in which they give their opinion of new films and plays. They are called critics, and their articles are called reviews. These are some words they may use:
moving: producing strong emotions, often of sadness; a positive word
violent: includes lots of scenes with fighting and death
powerful: has a big effect on our emotions
gripping: exciting and very interesting
good fun: used to describe a film that may not be very serious or important but is enjoyable slow: boring