/ Dictionary / Index T tobacco mosaic: Meaning and Definition of Find definitions for: tobac'co mosa"ic Pronunciation: [key] — Plant Pathol. Plant Pathol. a disease of the nightshade family of plants, particularly tobacco and tomato, caused by the tobacco mosaic virus and characterized by mottled leaves and yellowed, necrotic plants. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tobacco hornworm tobacco mosaic virus Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language