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
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...
There are eight major planets, but more than a million minor ones, including asteroids. If you discover one, you get the honor of naming it. The Dictionary of Minor Planet Names includes minor planets named for rock bands, jazz musicians, poets, and...