Quadrilateral สี่เหลี่ยม
A quadrilateral is a polygon in Euclidean plane geometry with four edges (sides)
and four vertices (corners).
Other names for quadrilateral include quadrangle (in analogy to triangle),
tetragon (in analogy to pentagon, 5-sided polygon, and hexagon, 6-sided polygon),
and 4-gon (in analogy to k-gons for arbitrary values of k).
https://en.wikipedia.org/wiki/Quadrilateral