A suspension is a heterogeneous mixture in which solute-like particles settle out of a solvent-like phase some time after their introduction.
We apply the word 'suspension' when particles are big enough to eventually settle. If the particles are too small to ever settle, they are said to form a colloid.
We use the terms 'solute-like' and 'solvent-like,' because we are dealing with a heterogeneous mixture, while the terms solute and solvent refer to solutions, which are homogeneous.