Trace impurity inserted into a semiconductor to alter its properties

Wiktionary Word definitions in Wiktionary
n. A substance added in small amounts to a pure semiconductor material to alter its conductive properties.

Wikipedia Word definitions in Wikipedia
A dopant , also called a doping agent , is a trace impurity element that is inserted into a substance (in very low concentrations) to alter the electrical or optical properties of the substance. In the case of crystalline substances, the atoms of the dopant ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Dopant \Dop"ant\ (d[=o]p"ant), n. a foreign substance added to a material to alter its properties; -- a process used. e.g., in making semiconductors from pure silicon in the manufacture of semiconductor chips and integrated circuits.