Sibilance
Pronunciation : Sib"i*lance, Sib"i*lan*cy
Part of Speech : n.
Definition : Defn: The quality or state of being sibilant; sibilation. Milton would not have avoided them for their sibilancy, he who wrote . . . verses that hiss like Medusa's head in wrath. Lowell.
Source : Webster's Unabridged Dictionary, 1913