What is does IV mean?

In Roman numerals, it is the number 4. In medical terms, it means intra-venous- something that is put into a vein of the body. Perhaps the most common application for this is administering fluids intravenously. A bag or bottle of fluid is connected to a needle by a tube, and the needle inserted into a vein. Fluid then drips and goes into the vein. Can be used to give fluids to someone that cannot drink, or to administer medicines mixed in the IV fluid.