Levorotatory \Le`vo*ro"ta*to*ry\ (-r[=o]"t[.a]*t[-o]*r[y^]), a. [Levo- + rotatory.]

(Chem. & Physics) Turning or rotating the plane of polarization towards the left; levogyrate, as levulose, left-handed quartz crystals, etc. [Written also l[ae]vorotatory.]

Source: Webster's Revised Unabridged Dictionary (1913)