kurfa -kur- gismu

x1 is a right-angled shape/form defined by set of vertices x2, dimensions x3 (default 2).

Also rectangle, square, rectilinear; square (= kubykurfa, pitkubykurfa), cube (= kurkubli), rectangle (= clakurfa), rhombus/diamond (= sa'orkurfa, sa'orpitkubli). See also bliku, kubli, tapla, salpo, tarmi.

In notes:

bliku
x1 is a block [3-dimensional shape/form] of material x2, surfaces/sides x3.
clakurfa
x1 is a rectangle with vertices x2 and dimensions x3, long in direction x4.
kubli
x1 is a cube/regular polyhedron/polygon of dimensions x2 (def. 3), surfaces/sides x3 (def. 6).
kubykurfa
x1 is a cube with vertices x2.
kukru
x1 is orthogonal/perpendicular/right/at right angle/rectified/square/normal to x2, where they (are projected to) intersect orthogonally at locus/on set x3, otherwise being utterly distinct (and not even on the same axis/scale) in sense x4
lo'u'a (exp!)
«lo» with a focus on truthfulness and non-groupness; old-style «lo».
piknofibre
x1 is a/the pycnofiber [hair-like structure/coating; body-part] of x2 at body location x3
pirmidi
x1 is a pyramid of base/side x2 and height x3
salpo
x1 is sloped/inclined/slanted/aslant with angle x2 to horizon/frame x3.
sa'orkurfa
x1 is a rhombus with vertices x2 and dimensions x3 with slope angle x4.
tapla
x1 is a tile/cake [shape/form] of material x2, shape x3, thickness x4.
tarmi
x1 [ideal] is the conceptual shape/form of object/abstraction/manifestation x2 (object/abstract).
vonjgatai
x1 is a quadrilateral (quadrangle)