A more thorough explanation:

Definition: Due day, also known as boon day, refers to a historical practice where copyhold tenants were required to perform base services for their lord without pay on specific days of the year. These services could include tasks such as reaping corn.

Example: In medieval England, due days were an important part of the feudal system. Copyhold tenants would have to work on the lord's land for a certain number of days each year, without receiving any payment. These days were known as boon days or due days.

Explanation: The example illustrates how due days were a form of unpaid labor that copyhold tenants were required to perform for their lord. These days were an important part of the feudal system and were used to maintain the lord's land and ensure that crops were harvested in a timely manner.