When you talk about the composition of something, you are referring to the way in which its various parts are put together and arranged.

The compositions of a composer, painter, or other artist are the works of art that they have produced.

A composition is a piece of written work that children write at school.

Composition is the technique or skill involved in creating a work of art.

Composition is the act of composing something such as a piece of music or a poem.