Dear Student,
The solution with more than two mixtures with homogenous phase is termed as true solution while of heterogeneous phase are termed as colloids.
The size of true solution particles are less than 1 nm (<1 nm) while of colloids are in the range of 1-1000 nm bigger than true solution particles.
Ex:- Mixing of sugar solution in water is true solution while smoke in atmospheric air is colloid.
Regards.