'lung-breathing' originates from the combination of 'lung' and 'breathing', where 'lung' refers to the respiratory organ and 'breathing' refers to the act of inhaling and exhaling air.

The term 'lung-breathing' evolved from the need to describe organisms that use lungs for respiration, distinguishing them from those that use gills or other methods.

Initially, it meant 'breathing with lungs', and this meaning has remained consistent in modern usage.