A pure substance that contains more than one atom is called a compound.
Explanation:
Compounds are formed by combination of atoms by a fixed ratio. They have their own characteristic features.
Pure substances are further broken down into elements and compounds. A compound can be destroyed by chemical means. It might be broken down into simpler compounds, into its elements or a combination of the two.
Example
H2SO4 which is formed by combination of three different atoms like H, S and O.
