Secondary

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