What is the difference between a transducer and a sensor?

Question

What is the difference between a transducer and a sensor?

Answer 1

A sensor is a more generic term for pretty much anything that senses or measures something.  A transducer is a more specific term referring to a device that converts one type of energy to another, for the purpose of either sending or receiving information (the information, in this case, could simply be  a measurement).

Answer 2

A transducer is a device, usually electrical, electronic, electro-mechanical, electromagnetic, photonic, or photovoltaic that converts one type of energy or physical attribute to another for various purposes including measurement or information transfer (for example, pressure sensors)

in short a thing a that transform one form of energy to another

A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument.

in short, a thing that converts detected energy into a signal.

therefore all sensor are transducer but not all transducer are sensor