Source : Webster's Revised Unabridged Dictionary (1913)

Symphytism \Sym"phy*tism\, n. [Gr. ? grown together.]
   Coalescence; a growing into one with another word. [R.]

         Some of the phrasal adverbs have assumed the form of
         single words, by that symphytism which naturally
         attaches these light elements to each other. --Earle.