contagion

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Disease transmission by direct or indirect contact.
2. n. A disease that is or may be transmitted by direct or indirect contact; a contagious disease.
3. n. The direct cause, such as a bacterium or virus, of a communicable disease.
4. n. Psychology The spread of a behavior pattern, attitude, or emotion from person to person or group to group through suggestion, propaganda, rumor, or imitation.
5. n. A harmful, corrupting influence: feared that violence on television was a contagion affecting young viewers.
6. n. The tendency to spread, as of a doctrine, influence, or emotional state.

Century Dictionary and Cyclopedia

1. n. Infectious contact or communication; specifically and commonly, the communication of a disease from one person or brute to another. A distinction between contagion and infection is sometimes adopted, the former being limited to the transmission of disease by actual contact of the diseased part with a healthy absorbent or abraded surface, and the latter to transmission through the atmosphere by floating germs or miasmata. There are, however, cases of transmission which do not fall under either of these divisions, and there are some which fall under both. In common use no precise discrimination of the two words is attempted. See epidemic and endemic.
2. n. Hence The communication of a state of feeling, particularly of moral feeling, or of ideas, from one person to another; especially, the communication of moral evil; propagation of mischief; infection: as, the contagion of enthusiasm; the contagion of vice or of evil example.
3. n. Contagium.
4. n. Pestilential influence; malarial or poisonous exhalations.
5. n. A contagious disease.

Wiktionary

1. n. A disease spread by contact
2. n. The spread or transmission of such a disease
3. n. The spread of anything harmful, as if it were such a disease
4. n. finance A situation in which small shocks, which initially affect only a few financial institutions or a particular region of an economy, spread to the rest of financial sectors and other countries whose economies were previously healthy.
5. n. finance A resulting recession or crisis developed in such manner.

GNU Webster's 1913

1. n. (Med.) The transmission of a disease from one person to another, by direct or indirect contact.
2. n. That which serves as a medium or agency to transmit disease; a virus produced by, or exhalation proceeding from, a diseased person, and capable of reproducing the disease.
3. n. The act or means of communicating any influence to the mind or heart.
4. n. obsolete Venom; poison.

WordNet 3.0

1. n. the communication of an attitude or emotional state among a number of people
2. n. an incident in which an infectious disease is transmitted
3. n. any disease easily transmitted by contact