Virus#Etymology

As virion (plural Viria, virions or virion ) or rarely Viron a single virus particle is called, which is in contrast to a virus outside a cell.

Virion consists of one or more nucleic acid molecules which are often surrounded by a protein capsule, the capsid. May be other proteins are, for example, enzymatic activities in the virion. For some viruses, the virion additionally consists of an outer lipid membrane of the virus envelope.