The term "heterogeneous" refers to a composition that is diverse or varied in nature. It often describes a mixture where different components can be distinctly identified and are not uniformly distributed, such as in a salad with various ingredients or in materials like concrete. In contrast, a homogeneous mixture has a uniform composition throughout. Heterogeneity can apply to various fields, including science, sociology, and economics, emphasizing the presence of differences within a system or population.