A more thorough explanation:

Term: nonae et decimae
Definition: In history, nonae et decimae were two payments made by church-farm tenants to the church. The first payment was for the rent of the land, and the second payment was a tithe. Example: A farmer who rented land from the church would have to pay nonae et decimae. Let's say the rent for the land was $100 per year, and the tithe was 10% of the farmer's harvest. If the farmer harvested 100 bushels of wheat, they would have to give 10 bushels to the church as part of their nonae et decimae payment. This definition explains that nonae et decimae were two payments made by church-farm tenants to the church. The example illustrates how a farmer would have to pay both the rent for the land and a tithe on their harvest as part of their nonae et decimae payment.