means The pair of spongy organs in your chest that draw in air and pass its oxygen into your blood while expelling carbon dioxide.

from From Old English 'lungen,' tracing back to a Proto-Germanic root meaning 'light' — the same family that gives us 'light' in weight. The lungs were literally the 'light' organs, the ones that float when tossed in water (butchers knew this). That logic echoes elsewhere: the English butcher's term 'lights' for animal lungs, and likely a cousin in the Russian word for lung, 'lyogkoye,' also built on 'light.'