Trapezium or trapezoid
Trapezium/Trapezoid (in USA) – is a triangle chopped in half horizontally. It’s shaped like a lobster trap. It is a shape with 4 sides but has a pair of opposite sides that are parallel.
A trap with a void (trapezoid) for a lobster is shaped like a trapezoid.
This trapezium has parallel sides at the top (5m) and the bottom (8m).
This trapezium also has parallel sides top and bottom, but is upside down. It is still a trapezium.