Source : Webster's Revised Unabridged Dictionary (1913)

Molasses \Mo*las"ses\, n. [F. m['e]lasse, cf. Sp. melaza, Pg.
   mela[,c]o, fr. L. mellaceus honeylike, honey-sweet, mel,
   mellis, honey. See {Mellifluous}, and cf. {Melasses}.]
   The thick, brown or dark colored, viscid, uncrystallizable
   sirup which drains from sugar, in the process of manufacture;
   any thick, viscid, sweet sirup made from vegetable juice or
   sap, as of the sorghum or maple. See {Treacle}.

Source : WordNet®

molasses
     n : thick dark syrup produced by boiling down juice from sugar
         cane; especially during sugar refining