Sunscreen gets its protective power from ingredients called sun filters, which fall into two groups. "Mineral" is the common name for inorganic filters, of which there are only two: zinc oxide and titanium dioxide. "Chemical" is the common name for organic filters, which are carbon-based compounds and cover multiple different ingredients. A mineral sunscreen uses only inorganic filters, a chemical sunscreen uses only organic filters, and a sunscreen that combines both is known as a hybrid.
Both types of filters mainly protect the skin by absorbing UV radiation. Mineral filters, along with a few organic ones, also reflect a small portion of it.