coffee ring

American  

noun

1. a coffeecake shaped like a ring, plain or fruited, often with a topping of raisins, ground nuts, and icing.

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Etymology

Origin of coffee ring

First recorded in 1920–25

Example Sentences

In recent papers they have examined the quantum mechanics of caffeine, the thermal properties of stovetop coffee-maker steam, the capillary action of the “coffee ring effect” and the low-viscosity-liquid dynamics of hot coffee.

From The Wall Street Journal

In the coffee ring effect, water drying at the edges is replenished from the center of the droplet, and that fluid flow carries particles to the edge, forming the dark ring.

From New York Times

“You can always sell them something else. Some dinner rolls, a coffee ring for tomorrow’s breakfast.”

From Literature

And over there – my mind has a coffee ring stain and a leather bookmark with tattered fringes peeking out the top.

From Scientific American

This is known as the "coffee ring effect," and recently, researchers have determined that the shape of the particles in the liquid is an important factor in creating this pattern.

From US News