Secondary may refer to:

Science and nature

Secondary emission In particle physics, secondary emission is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles. The term often refers to the emi ...

, of particles **

Secondary electrons Secondary electrons are electrons generated as ionization products. They are called 'secondary' because they are generated by other radiation (the ''primary'' radiation). This radiation can be in the form of ions, electrons, or photons with suffici ...

, electrons generated as ionization products * The secondary winding, or the electrical or electronic circuit connected to the secondary winding in a

transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...

Secondary (chemistry) Secondary is a term used in organic chemistry to classify various types of compounds (e. g. alcohols, alkyl halides, amines) or reactive intermediates (e. g. alkyl radicals, carbocations). An atom is considered secondary if it has two 'R' Groups ...

, a term used in organic chemistry to classify various types of compounds *

Secondary color A secondary color is a color made by color mixing, mixing of two primary colors in a given color space. Additive secondaries Light (RGB) For the human eye, good primary colors of light are red, green, and blue. Combining lights of these colo ...

, color made from mixing primary colors *

Secondary mirror A secondary mirror (or secondary) is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary. Secondary mirro ...

, second mirror element/focusing surface in a reflecting telescope *

Secondary crater Secondary craters are impact craters formed by the ejecta that was thrown out of a larger crater. They sometimes form radial crater chains. In addition, secondary craters are often seen as clusters or rays surrounding primary craters. The study of ...

s, often called "secondaries" *

Secondary consumer A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food