TRANQUILLITY
repose, quiet, placidity, serenity, tranquillity, tranquility
(noun) a disposition free from stress or emotion
tranquillity, tranquility, quietness, quietude
(noun) a state of peace and quiet
tranquillity, tranquility, quiet
(noun) an untroubled state; free from disturbances
Source: WordNet® 3.1
Etymology
Noun
tranquillity (usually uncountable, plural tranquillities)
the state of being tranquil
the absence of disturbance; peacefulness
the absence of stress; serenity
the quality of calm such as that experienced in places with mainly natural features and activities, free from disturbance from manmade ones.
Usage notes
• More common spelling in the UK; less common in the US.
Synonyms
• See also calm
Source: Wiktionary
Tran*quil"li*ty, n. Etym: [F. tranquillité, L. tranquillitas.]
Definition: The quality or state of being tranquil; calmness; composure.
Source: Webster’s Unabridged Dictionary 1913 Edition