lung (plural lungs) (anatomy) A biological organ that extracts oxygen from the air. 1913, Joseph C. Lincoln, chapter 7, in Mr. Pratt's Patients: 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.