Tarn it

 

Do you happen to know the definition of a tarn?

Well ...

This is from Travel Trivia's "16 Interesting Geography Terms You Should Know":

"A tarn is a small mountain lake that was formed by a glacier. The geographical term evolved from the old Norse term tjorn, which refers to a small mountain lake with no tributaries. Formed in hollow ground left behind by a melted glacier, tarns are often surrounded by steep slopes that create a natural amphitheater. Tarns can be found throughout the mountainous regions of the world, with North Wales being particularly famous for its glacial tarns. Visitors to this part of the world will be treated to many crystal-clear tarns surrounded by stunning views."

Below, a picture of Sprinkling Tarn, in England's Lake District, near Scafell Pike, which is probably more famous.