[1] : The Collaborative International Dictionary of English v.0.48

sibilation \sib`ila"tion\, n. l. sibilatio.
   utterance with a hissing sound; also, the sound itself; a
   hiss.
   1913 webster

         he, with a long, low sibilation, stared. --tennyson.
   1913 webster

[2] : WordNet (r) 2.0

sibilation
     n 1: a fricative sound especially as an expression of
          disapproval; "the performers could not be heard over
          the hissing of the audience" syn: hiss, hissing
     2: pronunciation with a sibilant hissing or whistling sound
        syn: assibilation
see also:
hiss hissing assibilation 

[3] : Moby Thesaurus II by Grady Ward, 1.0

36 moby thesaurus words for "sibilation":
   aphonia, artificial voice, broken speech, broken tones,
   broken voice, childish treble, choked voice, cracked voice, croak,
   crow, dysarthria, dyslalia, dyslogia, dysphasia, dysphonia,
   dysphrasia, falsetto, harshness, hawking voice, hiss, hoarseness,
   idioglossia, idiolalia, impairment of speech, lisp, lisping,
   loss of voice, muzzy speech, nasal tone, nasalization, quaver,
   shake, speech defect, speech impediment, tremor, twang

Sibilation >> S Words
Sibilation, definition of term: Sibilation
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