The Collaborative International Dictionary of English v.0.48:

Muriatic \Mu`ri*at"ic\, a. [L. muriaticus pickled, from muria
   brine: cf. F. muriatique.] (Chem.)
   Of, pertaining to, or obtained from, sea salt, or from
   chlorine, one of the constituents of sea salt; hydrochloric.
   [1913 Webster]

   Muriatic acid, hydrochloric acid, HCl; -- formerly called
      also marine acid, and spirit of salt. See
      hydrochloric, and the Note under Muriate.
      [1913 Webster]