1Attributive Designating the bacterium Corynebacterium pseudodiphtheriticum, which resembles the causal agent of diphtheria, C. diphtheriae, and is found in the nasopharynx of humans, but is non-pathogenic. Chiefly in "pseudodiphtheria bacillus". Compare pseudodiphtheritic. Now historical.

2Any of various forms of pharyngitis or tonsillitis resembling diphtheria, especially by the presence of a pseudomembrane. Now rare.