'hyperoxaemia' originates from Greek elements: 'hyper-' (Greek 'ὑπέρ') meaning 'over' or 'excess', combined with 'oxaemia' from 'oxys' (Greek 'ὀξύς', related to oxygen) and 'haima' (Greek 'αἷμα') meaning 'blood'.

'hyperoxaemia' was formed in modern medical English by combining 'hyper-' with the earlier medical term 'oxaemia' (also written historically as 'oxæmia'); British English preserved the spelling 'oxaemia' (with 'ae'), while American English later simplified this to 'oxemia', yielding the US variant 'hyperoxemia'.

Initially, components referred generally to 'sharp' or 'acid' (from 'oxys') and 'blood'; as knowledge of oxygen developed, the compound came to denote specifically an excess of oxygen in the blood rather than a general blood 'sharpness'.