'regularly-kept' originates from the combination of 'regularly' and 'kept', where 'regularly' means 'in a consistent manner' and 'kept' means 'maintained or preserved'.

'regularly-kept' evolved from the Middle English word 'regular' and the Old English word 'cepan', which meant 'to seize or hold'.

Initially, it meant 'maintained in a regular manner', and this meaning has largely remained the same in modern usage.