\Le"vo-\ (l[=e]"v[-o]-).
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 {l[ae]vo-}.]