I started studying French right after lockdown started this year. Totally coincidentally, my employer picked up a client who does significant business in Canada. They paid for all of the text in our software to be converted to French, and I've learned a lot working with it. But I've been told to add on bits and pieces of text in both English and French. Usually I can figure things out just by what I know and what the translator did. But I'm stuck here.

The English says "PO Number." The French, abbreviated for space, says "No bon de commande." I need to move this text somewhere that I don't need abbreviations, so I'd like to spell everything out. I get that "No" is short for "Numéro" and "comm" is short for "commande." But I can't figure out "bon." Is it an abbreviation for something? Collins says it might be the noun, meaning voucher. But a PO number isn't a voucher.

Collins separately offers "numéro de commande" for an "order number" and "ordre d'achat" for a "purchase order," but I'd like to use what the translator used if possible.