What is "undines"

Usage examples of "undines".

But we will widen our search, and there are friends of fresh water, like the undines, that we can call upon the wide world over.

Her teeth, unlike those of undines, were white, pearly, and exactly like human teeth.

When the sun shone, undines rose from the water and frolicked around the prow.

I was also aware that the undines that live in the Lagoon have a great deal to do with the Strega mages.