CURVILINEAR
curvilineal, curvilinear
(adjective) characterized by or following a curved line; “curvilinear tracery”; “curvilinear motion”
Source: WordNet® 3.1
Etymology
Adjective
curvilinear (not comparable)
(of a line) Having bends; curved; curvilineal.
(geometry, arts) Formed by curved lines.
Source: Wiktionary
Cur`vi*lin"e*al (-al), Cur`vi*lin"e*ar (-r), a. Etym: [L. curvus bent
+ E. lineal, linear.]
Definition: Consisting of, or bounded by, curved lines; as, a curvilinear
figure.
Source: Webster’s Unabridged Dictionary 1913 Edition