What is Composition ?
Composition is (noun) 1. how something is made up Scientists are trying to establish the composition of the rock sample from the moon. 2. something which has been composed, e.g. a poem or piece of music We will now play a well-known composition by Dowland. 3. an essay or piece of writing on a special subject We had three hours to write a composition on ‘pollution’.
source: Easier English, Student Dictionary Upper Intermediate Level