Silence
Silence was the absence of sound or noise.
When preparing Captain Jonathan Archer and Commander Trip Tucker for their visit of the Vulcan monastery at P'Jem in June 2151, Sub-commander T'Pol recited the proper protocols and told them to bow slightly and observe a respectful silence for approximately five seconds after they were offered the Stone of J'Kah. (ENT: "The Andorian Incident")