what is a virion
Definition of VIRION. : a complete virus particle that consists of an RNA or DNA core with a protein coat sometimes with external envelopes and that is the extracellular infective form of a virus.ADVERTISEMENT. French, from viri en viral (from virus virus) + -on 2 -on.First Known Use: 1959.edical Definition of VIRION. : a complete virus particle that consists of an RNA or DNA core with a protein coat sometimes with external envelopes and that is the extracellular infective form of a virus. Britannica.com: Encyclopedia article about virion.