A suspension is a heterogeneous mixture containing minute particles which are visible to the naked eye, if left undisturbed the particles in a suspension eventually settle. The components of a suspension can be separated by filtration.
Examples of suspensions:
Dust in air is a suspension of a solid in a gas.
Powder chalk in water is an example of a suspension of a solid in a liquid.
Muddy water is another example of a solid suspended in a liquid.