sonde vs timbre

sonde

noun
  • Probe; sound. 

  • Any of various devices for testing physical conditions, often for remote or underwater locations. 

timbre

noun
  • The quality of a sound independent of its pitch and volume. 

  • The pitch of a sound as heard by the ear, described relative to its absolute pitch. 

  • The crest on a coat of arms. 

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