id est
/(ˌ)ɪd ˈɛst/noun
Used to introduce an explanation of a word or phrase: that is to say.
- Now usually in the abbreviated form i.e. (formerly often i.): see i. i.e..
Origin
Old English; earliest use found in Bede's Ecclesiastical History. From classical Latin id est ‘that is’, used in works written in Latin to introduce an explanation of a word or phrase, ‘that is to say’ from id it + est, 3rd singular present indicative of esse to be.