The story
- Latin · derived fromplēnus“full”
- Late Latin · derived fromplēnārius
- Middle English · inherited fromplenarie
- English todayplenary
From Middle English plenarie, plenarye, from Late Latin plēnārius, from Latin plēnus (“full”).
Words from the same roots
Latinplēnus all →
plainreplenishplenalplenepleniloquenceplenipotentplenismplenistplenoptic
Etymology from Wiktionary, CC BY-SA 4.0.