electron By Ivan Suarez Robles 16 Nov, 2010 A negatively charged particle; one of the three basic kinds of particles that make up an atom. Electrons can either be free or orbit the nucleus of an atom.Related Articles: Glossary: oxidationMetal Accumulation in Huntington's DiseaseEthyl-EPA (Miraxion, LAX-101)NicotinamideDichloroacetate