allomorph

allomorph
    n 1: any of several different crystalline forms of the same
         chemical compound; "calcium carbonate occurs in the
         allomorphs calcite and aragonite"
    2: a variant phonological representation of a morpheme; "the
       final sounds of `bets' and `beds' and `horses' and `oxen' are
       allomorphs of the English plural morpheme"
    

Paramorph \Par"a*morph\, n. [Pref. para- + Gr. morfh` form.]
   1. (Min.) A kind of pseudomorph, in which there has been a
      change of physical characters, by a change in crystal
      structure without alteration of chemical composition, as
      the change of aragonite to calcite; called also
      {allomorph}.
      [1913 Webster +PJC]

   2. (Biol.) A taxonomic variant observed within a species, for
      which a more specific term has not been assigned.
      [PJC] -- {par`a*mor"phic}, a. -- {par`a*mor"phous}, a.
      [PJC]
    

Allomorph \Al"lo*morph\, n. [Gr. ? other + morfh` form.] (Min.)
      (a) Any one of two or more distinct crystalline forms of
          the same substance; or the substance having such
          forms; -- as, carbonate of lime occurs in the
          allomorphs calcite and aragonite.
      (b) A variety of pseudomorph which has undergone partial
          or complete change or substitution of material; --
          thus limonite is frequently an allomorph after pyrite.
          --G. H. Williams.
          [1913 Webster]