'full-length' originates from the combination of 'full' and 'length', where 'full' meant 'complete' and 'length' referred to 'extent or measurement'.

'full-length' evolved from the Old English word 'ful' meaning 'full' and 'lengþu' meaning 'length', eventually becoming the modern English word 'full-length'.

Initially, it meant 'complete in length', and this meaning has largely remained the same in modern usage.