Emily Dickinson Lexicon

IN-FEC'TION, n. [Fr. from L. inficio.]

1. The act or process of infecting.
2. The thing which infects. In medicine, the terms infection and contagion are used as synonymous in a great majority of cases. Different writers proposed and attempted to make a distinction between them, but there has been a great disagreement as to what the distinction should be; and in general no regard is paid to the proposed distinctions. Infection is used in two acceptations; first, as denoting the effluvium or infectious matter exhaled from the person of one diseased, in which sense it is synonymous with contagion; and secondly, as signifying the act of communication of such morbid effluvium, by which diseases is transferred. – Cyc.
3. That which taints, poisons or corrupts by communication from one to another; as, the infection of error or of evil example.
4. Contamination by illegality, as in cases of contraband goods.
5. Communication of like qualities. Mankind are gay or serious by infection. – Rambler.