The idea, opposite to
existentialism, that things have essences. For instance, in an essentialist view, there is an essense "horse" that exists seperately from any given individual horse; actual horses are just an instantiation of the essential concept "
horse".
In an
essentialist view, it is the essences which are the
true reality, and actual objects (or people) are just instantiations of those essences; "Essence precedes existence".