perpetual
per-PECH-oo-uladjMeaning never ending or changing; constant
Memory hook per-PET-ual: a PET whose tail never stops. Biscuit the dog wags his tail morning, noon and night; even in his sleep it thumps. His wagging is perpetual.
The perpetual drip of the leaky faucet kept Felix awake all night.
In context Living beside the waterfall meant perpetual noise: day and night, summer and winter, the roar never stopped.
Similar endless, constant, unending, everlasting
Opposite temporary, brief, intermittent
From Latin perpetuus, “continuing throughout.”