A more thorough explanation:

Term: Ingressus
Definition: Ingressus is a historical term that refers to the fee paid by an heir to a feudal lord to enter the estate of a deceased person. In feudal times, when a person died, their property and land would pass on to their heir. However, the heir had to pay a fee to the feudal lord to gain entry to the estate. This fee was known as ingressus.
Examples: If a lord died and his son inherited his estate, the son would have to pay a fee to the feudal lord to gain entry to the estate. This fee was known as ingressus. Another example would be if a knight died and his son inherited his land, the son would have to pay a fee to the feudal lord to gain entry to the land.
Explanation: The examples illustrate the definition of ingressus by showing how heirs had to pay a fee to the feudal lord to gain entry to the estate or land of a deceased person. This fee was a common practice in feudal times and was known as ingressus.