curvilinear

from WordNet (r) 3.0 (2006)

curvilinear
    adj 1: characterized by or following a curved line; "curvilinear
           tracery"; "curvilinear motion" [syn: {curvilineal},
           {curvilinear}]

from The Collaborative International Dictionary of English v.0.48

Curvilineal \Cur`vi*lin"e*al\ (-al), Curvilinear
\Cur`vi*lin"e*ar\ (-?r), a. [L. curvus bent + E. lineal,
   linear.]
   Consisting of, or bounded by, curved lines; as, a curvilinear
   figure.
   [1913 Webster]