bombination vs sibilant

bombination

noun

  • the act or sound of humming or buzzing; hum, buzz 

sibilant

noun

  • A consonant having a hissing or hushing sound such as the s or sh in sack or shack. 

adj

  • Characterized by a hissing or hushing sound such as the s or sh in sack or shack. 

How often have the words bombination and sibilant occurred in a corpus of books? (source: Google Ngram Viewer )