'lockbox' originates from Middle English, combining 'lock' from Old English 'loc' meaning 'fastening' and 'box' from Old English 'box' meaning 'container'.

'loc' and 'box' combined in Middle English to form 'lockbox', which has retained its meaning as a secure container.

Initially, it meant 'a box with a lock', and this meaning has largely remained the same in modern usage.