Types of mixtures
There are three general types of mixtures which are separated by the size of the particles present.
A solution is a mixture in which the solute is broken down into its smallest constituent parts. In other words, the solute is entirely broken down into individual ions or molecules.
A colloid is a mixture in which the solute is broken down into pieces that are too small to see with the naked eye, but are large enough to interfere with visible light. As a result, colloids are cloudy.
A suspension is a mixture in which the solute particles are large enough to be seen by the naked eye. In addition, the particles are large enough for gravity to cause them to settle.
So, in simplest terms, the difference between solutions, colloids and suspensions is the size of the solute particles.