The quality or state of being tranquil; calmness; composure.
Webster 1828 Edition
Tranquillity
TRANQUIL'LITY
,
Noun.
[L. tranquillitas.] Quietness; a calm state; freedom from disturbance or agitation. We speak of the tranquillity of public affairs, of the state, of the world, the tranquillity of a retired life, the tranquillity of mind proceeding from conscious rectitude.