Full Idea
Let us call properties that enjoy the distinction of being instantiated by every object in every possible world 'trivially essential properties'.
Gist of Idea
Properties are 'trivially essential' if they are instantiated by every object in every possible world
Source
Alvin Plantinga (World and Essence [1970], I)
Book Reference
Plantinga,Alvin: 'Essays in the Metaphysics of Modality' [OUP 2003], p.49
A Reaction
These would appear to be trivially 'necessary' rather than 'essential'. This continual need for the qualifier 'trivial' shows that they are not talking about proper essences.