Where does “bistrage” come from?

bistrage (French) comes from French -age, from Middle French -age, from Old French -age, from Old Occitan -atge, from Latin -āticum.

bistrage (French): darkening, blackening

Definitions

Step	Language	Word	Meaning
1	French	-age	Forming nouns with the sense of "action or result...
2	Middle French	-age	forms nouns with the sense of "action or result...
3	Old French	-age	forms nouns with the sense of 'action or result...
4	Old Occitan	-atge	suffix used to form masculine nouns
5	Latin	-āticum	—