To render concave, or increase the degree of concavity.
A playing card made concave for use in cheating.
One of the celestial spheres of the Ptolemaic or geocentric model of the world.
An indentation running along the base of a surfboard, intended to increase lift.
An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.
The vault of the sky.
An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.
A concave surface or curve.
Hollow; empty.
Satisfying the property that all segments connecting two points on the function's graph lie below the function.
Not convex; having at least one internal angle greater than 180 degrees.
Curved like the inner surface of a sphere or bowl.
To separate or scatter (things) as if by sieving.
To sieve or strain (something).
[+object] (archaic or old-fashioned) To scrutinise (someone or something) carefully so as to find the truth.
[+ through (object)] To carefully go through a set of objects, or a collection of information, in order to find something.