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

Applying this logic is known as the concavity test.

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

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

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

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

"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 trumpets sounding where the rocks were most uneven and made concavities, gave much delight by the resounding of seven or eight echoes to one sound.

From A Journal of the Swedish Embassy in the Years 1653 and 1654, Vol II. by Charles Morton