means The process of breathing air in and out, or more technically, the biological process by which cells break down food molecules to release energy.

from From Latin 'respirare,' to breathe again — built from 're-' (back, again) and 'spirare' (to breathe), the same 'spirare' that breathes through 'spirit,' 'inspire,' 'expire,' and 'conspire' (literally, to breathe together). The ancients felt breath and life and soul were one and the same thing, which is why so many of these words still carry a whiff of the divine.