Group A

noun

: any of various strains of a streptococcus (Streptococcus pyogenes) that include the causative agents of pharyngitis, scarlet fever, septicemia, some skin infections, rheumatic fever, and glomerulonephritis

—usually used attributively

Group A strep throat

Word History

First Known Use

1945, in the meaning defined above

Medical Definition

Group A

noun

-ˈā 

: the Lancefield group of beta-hemolytic streptococci that comprises all strains of a species of the genus Streptococcus (S. pyogenes) and that includes the causative agents of pharyngitis, scarlet fever, septicemia, some skin infections (as pyoderma and erysipelas), rheumatic fever, and glomerulonephritis

—usually used attributively

Group A streptococcal infections

compare group b