The story
- Old French · derived frompoitral
- Anglo-Norman · derived frompeitral
- French · derived frompoitrel
- English todaypoitrel
From Middle English: the form poitral is from central/Parisian French poitrel, "introduced into English apparently by Caxton"; the older form peitral (Middle English peitrel, paytrel, etc) was borrowed from Anglo-Norman peitral; both are from Old French poitral (modern French poitrail).
Etymology from Wiktionary, CC BY-SA 4.0.