viroid

noun

vi·​roid ˈvī-ˌrȯid 

: 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

Examples of viroid in a Sentence

Recent Examples on the Web

Originally considered pathogenic, other viroid infections were found to be symptomless or latent. — Discover Magazine, 31 Jan. 2025

Given the ubiquity of viroids in the plant world, finding something similar in bacteria makes perfect sense, says Hefferon, who studies disease-causing viroids in commercial crops such as potatoes. — Joanna Thompson, Scientific American, 16 Feb. 2024

Like viruses, viroids reproduce by invading healthy cells and reprogramming them to duplicate the viroid’s genetic makeup instead of the cell’s own. — Daniel E. Slotnik, New York Times, 8 May 2023

For now, the problem of the hop latent viroid has largely fallen to growers themselves. — Dan Adams, BostonGlobe.com, 3 Dec. 2022

Word History

Etymology

vir(us) + -oid entry 1

First Known Use

1971, in the meaning defined above

Rhymes for viroid

• thyroid
• antithyroid
• hyperthyroid
• hypothyroid
• parathyroid
• euthyroid

Medical Definition

viroid

1 of 2 noun

vi·​roid ˈvī-ˌrȯid 

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

viroid

2 of 2 adjective

1

: caused by a virus

viroid pneumonia

2

: of or relating to viroids