'Sibilation' definitions:

Definition of 'sibilation'

From: WordNet
noun
A fricative sound (especially as an expression of disapproval); "the performers could not be heard over the hissing of the audience" [syn: hiss, hissing, hushing, fizzle, sibilation]
noun
Pronunciation with a sibilant (hissing or whistling) sound [syn: sibilation, assibilation]

Definition of 'Sibilation'

From: GCIDE
  • Sibilation \Sib`i*la"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]

Synonyms of 'sibilation'

From: Moby Thesaurus