A more thorough explanation:

Term: Posteriority
Definition: Posteriority means something that comes after something else. It is the state of being subsequent. For example, if you are born after your sister, you have posteriority to her. In the past, this word was used to describe the relationships between a tenant and the lords they held land from. The tenant held the older tenancy "by priority" and the newer one "by posteriority." This means that the tenant had a higher status with the older lord and a lower status with the newer lord. Overall, posteriority is a way to describe something that comes after something else. It can be used to talk about birth order or social status.