ˈkȯk-, ˈkȯḵ-, ˈkōk-, ˈkäk- noun
Usage: usually capitalized K
Etymology: after Robert Koch died 1910 German bacteriologist
: the response of a tuberculous animal to reinfection with tubercle bacilli marked by necrotic lesions that develop rapidly and heal quickly and caused by hypersensitivity to products of the tubercle bacillus