viroid

¹vi·roid

noun \ˈvī-ˌrȯid\

Definition of VIROID

1

: a hypothetical symbiont resembling a virus that was formerly held to be present in cells, to be favorable to the host, and to tend to mutate to a virus

2

: any of two families (Pospiviroidae and Avsunviroidae) of subviral particles that consist of a small single-stranded RNA arranged in a closed loop without a protein shell and that replicate in their host plants where they may or may not be pathogenic