A virus is an infectious microorganism made up of a nucleic acid segment (either DNA or RNA) wrapped by a protein coat. A virus cannot multiply on its own; instead, it must infect cells and utilize host cell components to replicate itself.
Viruses do not have chromosomes in the traditional sense. Viruses, on the other hand, have a segmented genome.
A genome segment is a single, distinct fragment of nucleic acid among the many that make up a single viral genome.
The influenza A virus, for example, has a segmented genome with eight ss RNA segments.