What is compositional movement?

Answer 1

A classical piece of music is usually divided into movements, there is no limit to how many movements a piece has but as a general rule of thumb a symphony by Mozart has four movements. To explain this in a simple way; if you would classify a record by Lady Gaga as the "piece", then the tracks would be the "movements".

In a concert with Classical Music you rarely play only one movement of a piece, it's customary to play all the movements (the whole piece). They are usually also played with only a small break to allow the musicians to change their sheets (the papers with the notes they play after) and the audience are not expected to applaud until the whole piece is finished. Doing so is considered rude (interestingly enough this was not the case during Mozart and Beethoven's time, back then it was more of a circus actually - anything could happen!).