'normopneic' originates from combining elements in Latin and Greek: the combining form 'normo-' (from Latin 'norma') and the Greek root 'pne-'/'pnein' (via the combining form '-pneic'), where 'norma' meant 'square, rule' and 'pnein' meant 'to breathe'.

'normopneic' is a modern medical coinage formed by combining the prefix 'normo-' (denoting normal) with the Greek-derived element '-pneic' (relating to breathing). The term was created analogously to other clinical descriptors (e.g., 'apneic', 'dyspneic') and entered medical usage to mean 'having normal breathing.'

Initially the components referred separately to 'rule/normal' and 'to breathe', and when combined in modern medical English they came to mean specifically 'having normal respiration' (no significant shift beyond the medical specialization).