A syringe is a medical instrument used to inject or withdraw fluids. It consists of three main parts:

1. Barrel: A cylindrical tube, usually made of plastic or glass, that holds the liquid. It is clear to allow for measurement markings and visibility of the fluid.

2. Plunger: A rod that fits snugly inside the barrel. Pushing or pulling the plunger moves fluid in or out of the syringe.

3. Needle: A thin, hollow metal tube attached to one end of the barrel, designed to pierce skin.