- Meinong(namesake of the distinction being discussed)
- An Austrian philosopher from the late 1800s who developed theories about objects that don't exist, like fictional characters or impossible things.
- Sein(German philosophical terminology used by Hegel)
- Being; the ontological status an item has when it is real.
- Sosein(contrasted with Sein in Meinong's theory)
- A German philosophical term meaning 'being-such' or 'how something is'—basically, all the qualities and characteristics an object has, regardless of whether it actually exists.
- abstract objects(The target of Platonist ontological claims)
- Objects referred to by singular terms in literally true sentences that cannot be paraphrased away; includes mathematical objects (e.g., numbers), propositions, properties, relations, sentence types, possible worlds, logical objects, and fictional objects.
- impossible objects(another type of thing that subsists rather than exists)
- Things that contradict the laws of logic or physics, like a square circle or a married bachelor—they can be thought about and described even though they cannot exist.
- subsist(what abstract and impossible objects do in Meinong's theory)
- A philosophical term meaning 'to have a kind of existence or reality' without necessarily existing in the physical world—used for abstract things like numbers or ideas.