The absence of sound WordNet 3.0 & Open English WordNet

Silence is the absence of ambient audible sound, the emission of sounds of such low intensity that they do not draw attention to themselves, or the state of having ceased to produce sounds; this latter sense can be extended to apply to the cessation or absence of any form of communication, whether through speech or other medium. Wikipedia

Lack of audible sound. Wikipedia Disambiguation

Lack of audible sound or presence of sounds of very low intensity Wikidata

The complete lack of sound or noise. OmegaWiki

The absence of sound; quietness. Wiktionary

Absence of sound. Wiktionary (translation)

The absence of any sound. Wiktionary