Where does “pieça” come from?

pieça (Old Leonese) comes from Late Latin pettia, from Gaulish pettyā, from Proto-Celtic kʷezdis — piece, portion.

Ancestry of “pieça”, step by step

Step	Language	Word	Meaning
1	Late Latin	pettia	piece
2	Gaulish	pettyā	—
3	Proto-Celtic	kʷezdis	piece, portion

pieça — Etymology, Origin & Word History | Etymology Explorer