[1] : The Collaborative International Dictionary of English v.0.48

petrolatum \pet`rola"tum\, n. chem.  pharm.
   a semisolid unctuous substance, neutral, and without taste or
   odor, derived from petroleum by distilling off the lighter
   portions and purifying the residue. it is a yellowish,
   fatlike mass, transparent in thin layers, and somewhat
   fluorescent. it is used as a bland protective dressing, and
   as a substitute for fatty materials in ointments. --u. s.
   pharm.
   1913 webster

   note: petrolatum is the official name for the purified
         product. cosmoline and vaseline are commercial
         names for substances essentially the same, but
         differing slightly in appearance and consistency or
         fusibility.
         1913 webster
see also:
cosmoline vaseline 

[2] : The Collaborative International Dictionary of English v.0.48

cosmoline \cos"moline\ k?z"m?-l?n, n. prob. fr. cosmetic +
   l. oleum oil. chem.
   a substance obtained from the residues of the distillation of
   petroleum, essentially the same as vaseline, but of somewhat
   stiffer consistency, and consisting of a mixture of the
   higher paraffines; a kind of petroleum jelly.
   1913 webster

Cosmoline >> C Words
Cosmoline, definition of term: Cosmoline
cosmoline_pag1.html