/ Dictionary / Index C collar rot: Meaning and Definition of Find definitions for: col'lar rot" Pronunciation: [key] — Plant Pathol. Plant Pathol. a disease of plants, characterized by cankers that girdle the stem, caused by any of several fungi, as Alternaria solani. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. collar point collat. Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language