From PIE *lengwh- (light in weight) — the organ named for being the lightest of the viscera, the only one that floats.
Either of the pair of respiratory organs in the chest that draw in air and transfer oxygen to the blood.
From Old English 'lungen' (plural), from Proto-Germanic *lungw- (the light organ), from PIE *lengʷh- (light in weight, not heavy). The lung was named for being the lightest of the internal organs — the only one that floats in water. This same naming logic appears in other languages: the Latin