Concave
There are some meaning on the term " concave up". However, in most cases, a concave is a hallow curve. A half circle with an opening is also a concave. Concave up means to concave somethings.
The mold for a concave object is convex.The mold for a convex object is concave.
concave
concave
concave
The opposite of convex is concave. Concave shapes have an inward curve, while convex shapes have an outward curve.
Concave is a property of [irregular] polygons. A parallelogram cannot be concave.
plano concave
no concave mirror is in shape of concave mirror
Concave, because you can connect the corners from the outside.
concave=in convex=out
Concave
There are some meaning on the term " concave up". However, in most cases, a concave is a hallow curve. A half circle with an opening is also a concave. Concave up means to concave somethings.
Rectangle
concave
His glasses have a concave lens.