Source : Webster's Revised Unabridged Dictionary (1913)

Molecular \Mo*lec"u*lar\, a. [Cf. F. mol['e]culare. See
   {Molecule}.] (Phys. & Chem.)
   Pertaining to, connected with, produced by, or consisting of,
   molecules; as, molecular forces; molecular groups of atoms,
   etc.

   {Molecular attraction} (Phys.), attraction acting between the
      molecules of bodies, and at insensible distances.

   {Molecular weight} (Chem.), the weight of a molecule of any
      gas or vapor as compared with the hydrogen atom as a
      standard; the sum of the atomic weights of the
      constituents of a molecule; thus, the molecular weight of
      water ({H2O}) is 18.

Source : WordNet®

molecular weight
     n : (chemistry) the sum of the relative atomic masses of the
         constituent atoms of a molecule [syn: {relative molecular
         mass}]