Dictionary.net

[Latin] Of or pertaining to croup; associated with the formation of a false membrane like that of membranous croup; as C. tonsillitis. C. inflammation, inflammation whether diphtherial or not, associated with the formation of a superficial, readily removable membrane. Cf. Diphtheritic. C. pneumonia, acute lobar pneumonia.

Of the nature of croup.

Characterized by superficial fibrinous exudation like that of croup. Pertaining to, or resembling, croup.