n. The act of infecting.n. The communication of disease or of disease-germs, whether by contact with a diseased person or with morbid or noxious matter, contaminated clothing, etc., or by poisonous exhalations from any source. Compare contagion, 1.n. Contamination by illegality, as in possessing contraband goods, etc.n. That which infects, or by which some quality or state is communicated.n. That which taints, poisons, or corrupts by communication from one to another; contaminating influence: as, the infection of error, or of an evil example.n. That by which disease is or may be communicated; an infecting agency; morbific emanation or influence; virus.n. In grammar, a modification of a vowel-sound by another following, whereby the first takes on the sound of the second: applied to such modification in Celtic speech. Windisch, Irish Gram. (trans.).n. In biology, the hypothetical influence upon the tissues of the mother animal by the sperm of a male, such that subsequent offspring of the mother by other sires are infected with the characteristics of the first sire: a hypothesis invented to account for telegony. See telegony.