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Opposite of concave . A geometric shape is convex if all its edges point outwards. That is no part of it curves or faces inwards. If a shape is convex, a line segment drawn between any two points on the shape will always lie inside the shape. The figure above is a convex pentagon. No part of it is caved in and any line segment, such as the red one shown, linking two points on it always lies inside the shape. See also Concave definition.
The term concave is a term that defines the boundness of a curve or some geometric shape on a coordinate plane, now there is 2 types of concavity there is concave up or concave down, if its concave up it is bounded below and if it is concave down it is bounded above, howevere to answer your question no there is no such thing, however a trapezoid on ...