concavity

As with the proposed LCRT, the Arecibo Observatory took advantage of the natural concavity of its resident crater to focus distant radio waves.

From Salon ● Sep. 5, 2021

It’s that point on a curve where the sign of the curvature — the concavity — changes.

From New York Times ● Mar. 16, 2018

This notion is called the concavity of the function.

From Textbooks ● Mar. 30, 2016

Even before smartphones, feature phones were colloquially known as soapbars because they all adhered to the concavity of the human palm.

From The Verge ● Mar. 31, 2015

The concavity in the center of the bed is rectified by sleeping on a folded-up towel, and so forth.

From "Nickel and Dimed: On (Not) Getting By in America" by Barbara Ehrenreich

"Taking out too much fat was what led to the concavities and deformities we saw in the past," says Dr. Alexander Swistel, director of the Weill Cornell Breast Center in New York City.

From Time Magazine Archive

The antic conglomeration of bumps, bulges and concavities of the Morris Mechanic Theater in Baltimore fairly shouts that the play's the thing—and also divulges stair towers and mechanical equipment spaces.

From Time Magazine Archive

From the edges to the center they were worn down in oval concavities to half their thickness.

From Time Magazine Archive

Albers' work was mathematically precise; Arp's cloudy figures were elaborately pointless: in all their polished bulges, holes, twists and suave concavities there was nothing to stop the eye, the hand, or the mind.

From Time Magazine Archive

There were long lines of round buttresses and great concavities of rock, more like the famous Causses of southern France than anything I have ever seen.

From Across the Continent by the Lincoln Highway by Effie Price Gladding