Intravenous means "within a vein." Most often it refers to giving medicines or fluids through a needle or tube inserted into a vein. This allows the medicine or fluid to enter your bloodstream right away. For example, your health care provider may prescribe medicines to be given through a vein, or an intravenous (IV) line.
Stedman's Online Medical Dictionary. Available at: www.stedmansonline.com/content.aspx?id=mlrI1400022864&termtype=t. Accessed April 21, 2015.