Webster's Revised Unabridged Dictionary · 1913

Infectious disease

Infectious disease

(a)
Any disease caused by the entrance, growth, and multiplication of microorganisms in the body; a germ disease. It may not be contagious.
(b)
Sometimes, as distinguished from contagious disease, such a disease communicated by germs carried in the air or water, and thus spread without contact with the patient, as measles.