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.
Taber's Medical Dictionary Online website. Intravenous. www.tabers.com/tabersonline/view/Tabers-Dictionary/740587/0/intravenous?q=Intravenous. Accessed June 11, 2019.