Lung (noun)

Either of the two large, spongy organs in the chest of mammals that are used for breathing.

Origin:

From middle english lunge, from old english lungen, from proto-germanic *lungōną.

Examples:

1. The lungs are responsible for taking in oxygen and expelling carbon dioxide.
2. She had a lung transplant after years of smoking.
3. The doctor listened to his lungs with a stethoscope.
4. The lungs of a bird are much more efficient than those of a human.
5. The lungs of the city were filled with smog.