viroid

noun vi·roid \ ˈvī-ˌrȯid \

Definition of viroid

: 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

Origin and Etymology of viroid

New Latin virus + English -oid

NEW! Time Traveler

First Known Use: 1971

in the meaning defined above

See Words from the same year

Medical Dictionary

viroid

noun vi·roid \ ˈvī-ˌrȯid \

medical 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