'slowly-changing' originates from the combination of 'slowly' and 'changing', where 'slowly' is derived from Old English 'slāwlice', meaning 'in a slow manner', and 'changing' from Old English 'cierran', meaning 'to turn or alter'.

'slowly' evolved from Old English 'slāwlice', and 'changing' from 'cierran', eventually forming the modern English term 'slowly-changing'.

Initially, 'slowly' meant 'in a slow manner', and 'changing' meant 'to alter', which together describe a gradual transformation.