Common Medieval Terms and Concepts Defining Universals

haeccaeity:
"thisness;" the individuality that makes something to be an ultimate
reality different from any other reality.


perseity:
"isness;" the existence that which makes something exist independently.


quidity:
"suchness;" the essence that which makes something to be a particular type.


necessity:
"mustness;" necessity that which makes something need/cause another.