The Collaborative International Dictionary of English v.0.48:

Hydrochloric \Hy`dro*chlo"ric\, a. [Hydro-, 2 + chloric: cf. F.
   hydrochlorique.] (Chem.)
   Pertaining to, or compounded of, chlorine and hydrogen gas;
   as, hydrochloric acid; chlorhydric.
   [1913 Webster]

   Hydrochloric acid (Chem.), hydrogen chloride; a colorless,
      corrosive gas, HCl, of pungent, suffocating odor. It is
      made in great quantities in the soda process, by the
      action of sulphuric acid on common salt. It has a great
      affinity for water, and the commercial article is a strong
      solution of the gas in water. It is a typical acid, and is
      an indispensable agent in commercial and general chemical
      work. Called also muriatic acid and chlorhydric acid.
      [1913 Webster]

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]

WordNet (r) 3.0 (2006):

muriatic acid
    n 1: a former name for hydrochloric acid