A more thorough explanation:

Banality is a historical legal term used in French Canada. It refers to a lord's right to force his vassals to use his own winepress, oven, mill, or other equipment.

For example, if a lord owned a mill, he could require his vassals to bring their grain to his mill to be ground into flour. The vassals would have to pay a fee for this service, and the lord would make a profit from it.

Another example would be if a lord owned an oven, he could require his vassals to use it to bake their bread. Again, the vassals would have to pay a fee for this service, and the lord would make a profit from it.

These examples illustrate how the lord had control over the economic activities of his vassals. The banality was a way for the lord to extract wealth from his vassals and maintain his power over them.