Orchestration in music can have two meanings:

1. It can mean: the study of how to write music for an orchestra.
2. It can also mean the list of instruments that are used in a particular piece of music.

People who want to compose music for orchestras need to study orchestration. They can do this by reading books about orchestration, but also they can do this by studying orchestral scores and listening to orchestras in concerts or on CDs. Students at music colleges will also practise orchestration by taking piano music and arranging it for orchestra.