The quality or state of being tranquil; serenity.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "tranquillity" in a sentence
"Another reason for this tranquillity is the habit of gambling, in which they have indulged from childhood, and which has taught them that neither high words nor violence will restore"
"But with a people who have once tasted the sweets of liberty, this kind of tranquillity is short."
"Way too many aspiring poets have rallied behind that banner, too few going so far as recollecting those emotions in tranquillity, let alone reading the rest of the preface to Lyrical Ballads (which can be found on Bartleby, for those interested)."