'autotransfusion' originates from Modern English, combining the prefix 'auto-' from Greek 'autos' meaning 'self' and the word 'transfusion' (from Latin 'transfusio') meaning 'a pouring across or transfer of fluid'.

'transfusion' comes from Latin 'transfundere' ('trans-' meaning 'across' + 'fundere' meaning 'to pour'), passed into Medieval/Modern French as 'transfusion' and then into English; 'autotransfusion' was formed in English by prefixing 'auto-' to 'transfusion'.

Initially related to the literal sense of 'pouring across' or transferring fluid; over time it became a specific medical term meaning 'the reinfusion of a patient's own blood'.