The story
- Italian · derived frompane“bread”
- Latin · derived frompānem
- English todaypannum
Compare Norwegian Rodi cant pannom/panum, meaning loaf; Swedish Månsing cant pan (“loaf”), and old jargon Dutch paen (“bread”). Having in mind the fact that Rodi and Månsing tend to have many Latin borrowings, it is likely that English pannum is also derived from Latin pānem, the accusative of pānis (“bread, loaf”). But it also may be through Italian pane (“bread”), in the light of that the English thieves' cant is known to have some Italian borrowings as well.
Etymology from Wiktionary, CC BY-SA 4.0.