diphtheroid

US: (dif′thə roid′, dip′-)

WordReference Random House Unabridged Dictionary of American English © 2026

diph•the•roid  (dif′thə roid′, dip′-), adj. [Pathol.]

1. Pathology resembling diphtheria, esp. in the formation of a false membrane in the throat.

n. 

2. Microbiology, Pathology any bacterium, esp. of the genus Corynebacterium, that resembles the diphtheria bacillus but does not produce diphtheria toxin.

• diphther(ia) + -oid 1860–65