The word 'heterogeneous' is the antonym of 'homogeneous'. A heterogeneous mixture is a collection of different materials in any mix. The term is used as a broad reference to a subject, rather than a definitive description. Heterogeneous mixtures may describe social, ideological or other concepts, referring to the mix of people or ideas, etc. The usage also implies that the general grouping has different properties, elements, or interactions within it.
Examples of Heterogeneous Mixture:
A heterogeneous group of people from all walks of life and backgrounds.
A random heterogeneous grouping of elements, like a rock, a needle, a diaper and a car.