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.

Expunge the whole, or lip the excrescent parts. --Pope.

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

Source: Webster's Revised Unabridged Dictionary (1913)