The Collaborative International Dictionary of English v.0.48:

molal \molal\ adj. (Chem.)
   Being at a concentration with the designated number of moles
   (of solute) per 1000 grams of solvent; as, an 0.5 molal
   solution of glycerol in water. Compare molar.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

molal
    adj 1: designating a solution containing one mole of solute per
           kilogram of solvent