contagious disease

from the GNU version of the Collaborative International Dictionary of English.

• (Med.) A disease communicable by contact with a patient suffering from it, or with some secretion of, or object touched by, such a patient. Most such diseases have already been proved to be germ diseases, and their communicability depends on the transmission of the living germs. Many germ diseases are not contagious, some special method of transmission or inoculation of the germs being required.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any disease easily transmitted by contact