Secondary may refer to:

Science and nature

* Secondary emission, of particles ** Secondary electrons, electrons generated as ionization products * The secondary winding, or the electrical or electronic circuit connected to the secondary winding in a transformer * Secondary (chemistry), a term used in organic chemistry to classify various types of compounds * Secondary color, color made from mixing primary colors * Secondary mirror, second mirror element/focusing surface in a reflecting telescope * Secondary craters, often called "secondaries" * Secondary consumer, in ecology * An antiquated name for the

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

in geosciences * Secondary feathers, flight feathers attached to the ulna on the wings of birds

Society and culture

* Secondary (football), a position in American football and Canadian football * Secondary dominant in music * Secondary education, education which typically takes place after six years of primary education **

Secondary school A secondary school, high school, or senior school, is an institution that provides secondary education. Some secondary schools provide both ''lower secondary education'' (ages 11 to 14) and ''upper secondary education'' (ages 14 to 18), i.e., b ...

, the type of school at the secondary level of education * Secondary market, an aftermarket where financial assets are traded

Science and nature

Society and culture

See also