Definition of "lung"

lung

/ˈlʌŋ/

noun
plural lungs
1. (anatomy) A biological organ of vertebrates that controls breathing and oxygenates the blood.
  Quotations
  I made a speaking trumpet of my hands and commenced to whoop “Ahoy!” and “Hello!” at the top of my lungs. […] The Colonel woke up, and, after asking what in brimstone was the matter, opened his mouth and roared “Hi!” and “Hello!” like the bull of Bashan.
  1913, Joseph C. Lincoln, chapter 7, in Mr. Pratt's Patients
2. (in the plural) Capacity for exercise or exertion; breath.
3. That which supplies oxygen or fresh air, such as trees, parklands, forest, etc., to a place.
  Quotations
  Afterwards he found that the vague feeling of alarm had spread to the clients of the underground railway, and that the Sunday excursionists began to return from all the South-Western "lungs" - Barnes, Wimbledon, Richmond Park, Kew, and so forth - at unnaturally early hours[.]
  1898, H.G. Wells, The War of the Worlds, London: William Heinemann, page 123