The Collaborative International Dictionary
Levo-
Levo- \Le"vo-\ (l[=e]"v[-o]-) pref. A prefix from L. laevus, meaning:
Pertaining to, or toward, the left; as, levorotatory.
(Chem. & Opt.) Turning the plane of polarized light to the left; as, levotartaric acid; levoracemic acid; levogyratory crystals, etc. [Written also l[ae]vo-.]
Douglas Harper's Etymology Dictionary
levo-
word-forming element meaning "toward the left," from French lévo-, from Latin laevus "left" (see left (adj.)).
Wiktionary
levo-
alt. (context chemistry English) Denoting a levorotatory form of an enantiomer. pre. (context chemistry English) Denoting a levorotatory form of an enantiomer.