/ Dictionary / Index V viroid: Meaning and Definition of Find definitions for: vi•roid Pronunciation: (vī'roid), [key] — n. an infectious agent of plants similar to a virus but consisting of only a short, single strand of RNA without a protein coat. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: viroid (Thesaurus) virl virology Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language