'Priest's' in the Bible

The chief of all the leaders of the descendants of Levi was Aaron the priest's son Eleazar. He was assigned to oversee those who were in charge of the services of the sanctuary.

This is the work of the tribes of the descendants of Merari with reference to their service at the Tent of Meeting under the supervision of Aaron the priest's son Ithamar."

After the plague was over, the LORD told Moses and Aaron the priest's son Eleazar,