fairy ring
n.— «Some sediment dweller has built its mound hard against a nodule. And on the left is a “fairy ring” of unknown origin that seems to be slipping and perhaps rolling nodules into its moat.» —“Why are there any nodules at all?” by Richard A. Kerr Science Feb. 10, 1984. (source: Double-Tongued Dictionary)
Further reading
What if, instead of being an inanimate object, a dictionary were alive? That’s the idea behind a lavishly illustrated new children’s book called The Dictionary Story (Bookshop|Amazon) by Oliver Jeffers and Sam Winston. This is part of a...
Cat hair may be something you brush off, but cat hair is also a slang term that means “money.” In the same way, cat beer isn’t alcoholic — some people use cat beer as a joking term for “milk.” And imagine walking on a...