Stethoscope (noun)

1. A medical instrument for listening to the internal sounds of a human body, especially the heart and lungs.
2. A device for listening to sounds in an engine, machinery, or other machine.

Origin:

The word 'stethoscope' originated from the greek words 'stethos' meaning 'chest' and 'skopein' meaning 'to examine'.

Examples:

1. The doctor used a stethoscope to listen to the patient's heart.
2. She listened to the engine with a stethoscope to identify the source of the noise.
3. The stethoscope is an essential tool for any doctor.
4. The sound of the heartbeat could be heard clearly through the stethoscope.
5. The mechanic used a stethoscope to diagnose a problem in the car engine.