Source : Webster's Revised Unabridged Dictionary (1913)

Lac \Lac\, Lakh \Lakh\, n. [Hind. lak, l[=a]kh, l[=a]ksh, Skr.
   laksha a mark, sign, lakh.]
   One hundred thousand; also, a vaguely great number; as, a lac
   of rupees. [Written also {lack}.] [East Indies]

Lac \Lac\, n. [Per. lak; akin to Skr. l[=a]ksh[=a]: cf. F.
   lague, It. & NL. lacca. Cf. {Lake} a color, {Lacquer},
   {Litmus}.]
   A resinous substance produced mainly on the banyan tree, but
   to some extent on other trees, by the {Coccus lacca}

Source : WordNet®

lac
     n : resinlike substance secreted by certain lac insects; used in
         e.g. varnishes and sealing wax