pos>pref. 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-. ] [ 1913 Webster ]

a. [ Levo- + DOPA, dihydroxyphenylalanine. ] (Chem. & Biochem.) A substance used as a therapy for Parkinson's Disease; the L form of Dopa; L-dihydroxyphenylalanine; L-hydroxytyrosine (C9H11NO4); also called L-dopa. In the body it is converted by the enzyme dopa-decarboxylase into dopamine, the form in which it is active in the brain, affecting neural impulse transmission. [ PJC ]

a. [ Levo- + gyrate. ] (Chem., Physics, Biochem.) Turning or twisting the plane of polarization of light towards the left, as levulose, levotartaric acid, etc.; levorotatory. [ Written also lævogyrate. ] [ 1913 Webster ]

a. [ Levo- + rotary. ] (Chem. & Physics) Same as levorotatory. [ PJC ]

n. [ Written also lævorotation. ] [ Levo- + rotation. ] (Physics & Chem.) Rotation in the direction of an outgoing right-handed screw; counter-clockwise rotation; -- applied chiefly to the turning of the plane of polarization of light. [ Webster 1913 Suppl. ]

a. [ Levo- + rotatory. ] (Chem. & Physics) Turning or rotating the plane of polarization of light towards the left; -- applied to crystals and compounds exhibiting optical activity, such as levulose, left-handed quartz crystals, etc. Opposite of dextrorotatory. [ Written also lævorotatory. ] [ 1913 Webster +PJC ]