germ theory

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The doctrine holding that infectious diseases are caused by the activity of microorganisms within the body.

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

• (Biol.) The theory that living organisms can be produced only by the development of living germs. Cf. biogenesis, abiogenesis.
• (Med.) The theory which attributes contagious and infectious diseases, suppurative lesions, etc., to the agency of germs, i.e. pathogenic microorganisms. The science of bacteriology was developed after this theory had been established.

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

• noun (medicine) the theory that all contagious diseases are caused by microorganisms