Where does “tranquility” come from?

Tranquility comes from English tranquil plus the suffix -ité, from French tranquille and Latin -itas, ultimately from Proto-Indo-European terh₂-, meaning to cross or overcome.

tranquility (English): Alternative spelling of tranquillity

Definitions

Alternative spelling of tranquillity

Ancestry of “tranquility”, step by step

Step	Language	Word	Meaning
1	English	tranquillity	the state of being tranquil; the absence of...
2	Middle English	tranquillite	—
3	Old French	tranquillite	—
4	Latin	tranquillitās	—
5	Latin	Tranquillus	—
6	Latin	trānsquīlus	—
7	Latin	quiēs	—
8	Proto-Italic	kʷiētis	—
9	Proto-Indo-European	kʷyéh₁tis	—
10	Proto-Indo-European	kʷyeh₁-	to rest; rest, peace

Every word from Proto-Indo-European kʷyeh₁- →

tranquility — Etymology, Origin & Word History | Etymology Explorer