A syringe is a medical device used to inject fluids into or withdraw fluids from the body. It typically consists of a cylindrical barrel, a plunger, and a needle. Syringes come in various sizes and are commonly used for administering medications, vaccines, and drawing blood. Syringes can be made from plastic or glass and are often disposable to ensure safety and prevent infection. They are essential tools in healthcare settings, used by professionals like nurses and doctors, as well as for home use in managing conditions like diabetes with insulin.