The story
- Latin · derived fromVetus Testāmentum
- Middle English · inherited fromOlde Testament
- English todayOld Testament
From Middle English Olde Testament, calqued from Latin Vetus Testāmentum. Old refers to ancientness, not to obsolescence. Equivalent to a retronym, by comparison with the New Testament.
Etymology from Wiktionary, CC BY-SA 4.0.