/ Dictionary / Index A aster yellows: Meaning and Definition of Find definitions for: as'ter yel'lows Pronunciation: [key] — Plant Pathol. Plant Pathol. a dwarfing and yellowing of asters and various other plants, caused by a mycoplasma transmitted by a leafhopper. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Asteropaeus asthenia Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language