kruvi -ruv-kru- gismu

x1 is a curve/turn/bend in x2, at locus x3, and defined by set of points/properties x4.

(adjective:) x1 is curved; (x4 as a set of points is sufficiently specified to identify the relevant properties of the bend). See also korcu, bargu, genxu, linji, sirji.

In notes:

x1 arches/curves over/around x2 and is made of x3; x1 is an arch over/around x2 of material x3.
x1 is a hook/crook [shape/form] of material x2.
(adjective:) x1 is bent/crooked/not straight or direct/[twisted]/folded.
x1 is a line/among lines [1-dimensional shape/form] defined by set of points x2.
x1 is straight/direct/line segment/interval between x2 and x3; (adjective:) x1 is linear.