Source : Webster's Revised Unabridged Dictionary (1913)

Serous \Se"rous\, a. [Cf. F. s['e]reux. See {Serum}.] (Physiol.)
   (a) Thin; watery; like serum; as the serous fluids.
   (b) Of or pertaining to serum; as, the serous glands,
       membranes, layers. See {Serum}.

   {Serous membrane}. (Anat.) See under {Membrane}.

Source : WordNet®

serous
     adj : of or producing or containing serum; "a serous exudate"