An unending source of sustenance, it provided a crucial role in the development of Egyptian civilization.

He loved his Machines and that love was an unending source of happiness to him.

The doomsday predictions for the Giants' opening game - and the season in general - have proved an unending source of motivation.

He called star-moles "a gold mine for discoveries about brains and behavior in general-and an unending source of surprises".

Ground water, in huge underground lakes, or aquifers, were considered unending sources of pure water.

And what's the source of this magical, unending source of free and clean energy?

People think of Arrakis as an unending source of riches, and they don't care about the mechanics or the details.

Grandmama Sarah was an unending source of biscuits, toffee and other delights.

It provided an unending source of interest.

The New World was a vast laboratory for experimentation and an unending source of samples.