Le"vo- (lē"v&osl;-). A prefix from L. laevus, meaning: (a) Pertaining to, or toward, the left; as, levorotatory. (b) (Chem. & Opt.) Turning the plane of polarized light to the left; as, levotartaric acid; levoracemic acid; levogyratory crystals, etc. [Written also lævo-.]