Function: noun
Date: 1923
1 : any of various plant diseases caused by viruses (genus Nepovirus of the family Comoviridae ) and marked by circular lesions of usually chlorotic or necrotic tissue
2 : a turf disease caused by an ascomycetous fungus ( Leptosphaeria korrae syn. Ophiosphaerella korrae ) and marked by circular patches or rings of dead grass