“A colloid is a heterogeneous system in which one substance is dispersed (dispersed phase) as very fine particles in another substance called a dispersion medium.”
The dispersed phase of a colloid can be made up of single macromolecule particles such as protein or an aggregate of numerous atoms, ions, or molecules.
Examples of colloid
Milk, whipped cream, and butter are examples of colloid.
Gold sol is also an example of a colloid. It may contain particles of various sizes having many atoms.