syringe syringe a syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. the plunger can be linearly pulled and pushed along the inside of the tube, allowing the syringe to take in and expel liquid or gas through a discharge orifice at the front (open) end of the tube. the open end of the syringe may be fitted with a hypodermic needle, a nozzle or tubing to direct the flow into and out of the barrel. syringes are frequently used in clinical medicine to administer injections, infuse intravenous therapy into the bloodstream, apply compounds such as glue or lubricant, and draw/measure liquids. there are also prefilled syringes (disposable syringes marketed with liquid inside). disposable syringe with needle, with parts labelled: plunger, barrel, needle adaptor, needle hub, needle bevel, needle shaft a typical plastic medical syringe, fitted with a detachable stainless steel needle according to the world health organization, about 90% of the medical syringes are used to administer drugs, 5% for vaccinations and 5% for other uses such as blood transfusions. the word "syringe" is derived from the greek σύριγξ (syrinx, meaning "pan flute", "tube"). medical syringes