1. Injection of fluid into the body other than orally. Fluid may be injected into tissue spaces, the rectum, or the abdominal cavity. This technique is used to inject fluids parenterally when venipuncture is not possible. Parentarally refers to any medication route other than the alimentary canal; such as, intravenous, subcutaneous, intramuscular, or mucosal.
2. An infusion of fluid, usually subcutaneously, for therapeutic purposes.
3. Formerly, a fluid enema, later, the washing out of material from any body space or cavity by fluids by injection or lavage (a washing; especially, in medicine as in the washing out of a bodily organ).