Definition of tar spot
1a : a leaf-blotch disease of maple, willow, or oak caused by fungi of the genus Rhytisma that produces raised black stromatic cushions on the foliage
b : one of the spots produced
2 : a disease of many grasses caused by a fungus (Phyllacora graminis) and resembling the tar spot of trees
Keep scrolling for more
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
- 'Conscience' vs. 'Conscious': Let Us Be Your Guide
- Hot Enough for You? Words for the Summer Heat
- Where Does 'Run-of-the-Mill' Come From?
- The Provenance of 'Providence'
Ask the Editors
- On Contractions of Multiple Words
- A Look at Uncommon Onomatopoeia
- Is Singular 'They' a Better Choice?