Webster’s Revised Unabridged Dictionary · 1913
Infectious disease
In·fec′tious dis·ease′. (a) Any disease caused by the entrance, growth, and multiplication of bacteria or protozoans 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.