1. A pressure transducer is a sensor used to measure pressure. Depending on where you put it and how you connect it, a pressure transducer can tell you the pressure in a pipe or tank, the weight of an object, or even the depth of fluid above it. Most industrial pressure transducers are made of two technical parts, a transducer and a transmitter, inside a third, equally important part, the housing.
2. A transducer converts a physical action--often a vibration--into an electrical signal. Microphones and the pickups on an electric guitar, which both convert sound waves into electrical signals, are transducers. Pressure transducers, then, convert pressure--air pressure, fluid pressure, oil pressure, etc.--into electrical signals.