The Collaborative International Dictionary of English v.0.48:

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.
       [1913 Webster]

   Serous membrane. (Anat.) See under Membrane.
      [1913 Webster] Serow

WordNet (r) 3.0 (2006):

serous
    adj 1: of or producing or containing serum; "a serous exudate"

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "serous":
   bloody, chylifactive, chylifactory, chylific, excretory, humoral,
   ichorous, lachrymal, lachrymose, lacrimatory, lactational, lacteal,
   lacteous, phlegmy, purulent, pussy, rheumy, salivant, salivary,
   salivous, sanious, secretional, secretive, secretory, seminal,
   sialagogic, spermatic, suppurated, suppurating, suppurative,
   tearlike, watering, watery