Hollowed out or rounded inward
The opposite of convex is concave. Concave shapes have an inward curve, while convex shapes have an outward curve.
Concave, because you can connect the corners from the outside.
Concave is a property of [irregular] polygons. A parallelogram cannot be concave.
plano concave
no concave mirror is in shape of concave mirror
concave=in convex=out
concave
His glasses have a concave lens.
Rectangle
concave
concave
Yes, a triangle is always concave. * * * * * How wrong can you get! A triangle is always convex and NEVER concave.