'backstroke' originates from English, specifically the compound of 'back' + 'stroke', where 'back' meant 'the rear' and 'stroke' meant 'a movement or blow (with the arm).'

'backstroke' was formed in English (late 19th century) as a compound describing a swimming movement ('back' + 'stroke') and became established as the name of the swimming style 'backstroke'.

Initially it described a 'stroke (movement) made with the back facing the water or a backward stroke', but over time it specialized to denote the specific swimming style now called 'backstroke'.