It occurs when the cartilage covering the end of the bones gradually wears away.

The trouble is that the plot's often obscure grotesqueness gradually wears the reader down.

With the court providing no practical support, the French gradually wore down the partisans.

The hunt lasted several hours, and gradually wore down the filmmakers.

Day wore gradually into night, and fog cloaked what little visibility remained.

The idea was that it would gradually wear away, and indeed it faded to good effect in two years.

Like everything else, however, the excitement gradually wore away, though ever after occasionally pop-guns might be heard at all hours of the day.

He gradually wore the leader down around the stretch turn and led Rock Point by a length after a mile in 1:38 2/5.

The cartilage in the knee gradually wears away, causing pain and swelling.

Yes, most definitely the battery was gradually wearing down, which was to be expected since he had the light on all the time.