arch rim

from The Collaborative International Dictionary of English v.0.48
Rim \Rim\, n. [As. rima, reoma, edge; cf. W. rhim, rhimp, a rim,
   edge, boundary, termination, Armor, rim. Cf. {Rind}.]
   1. The border, edge, or margin of a thing, usually of
      something circular or curving; as, the rim of a kettle or
      basin.
      [1913 Webster]

   2. The lower part of the abdomen. [Obs.] --Shak.
      [1913 Webster]

   {Arch rim} (Phonetics), the line between the gums and the
      palate.

   {Rim-fire cartridge}. (Mil.) See under {Cartridge}.

   {Rim lock}. See under {Lock}.
      [1913 Webster]
    

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