excrescent letter

from The Collaborative International Dictionary of English v.0.48
Excrescent \Ex*cres"cent\, a. [L. excresens, -entis, p. pr. of
   excrescere to grow out; ex out + crescere to grow. See
   {Crescent}.]
   Growing out in an abnormal or morbid manner or as a
   superfluity.
   [1913 Webster]

         Expunge the whole, or lip the excrescent parts. --Pope.
   [1913 Webster]

   {Excrescent letter} (Philol.), a letter which has been added
      to a root; as, the d in alder (AS. alr) is an excrescent
      letter.
      [1913 Webster]
    

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