In metaphysics, particulars are, one might say, identified by what they are not: they are not abstract, not multiply instantiated. (Though there is a potentially confusing piece of jargon that seems to contradict this: instances of properties are sometimes called abstract particulars.) Hence, Socrates is a particular (there's only one Socrates-the-teacher-of-Plato and one cannot make copies of him, e.g., by cloning him, without introducing new, distinct particulars). Redness, by contrast, is not a particular, because (it is held by metaphysical realists) it is abstract and multiply instantiated (my bicycle, this apple, and that girl's hair are all red). Metaphysics (Greek words meta = after/beyond and physics = nature) is a branch of philosophy concerned with the study of first principles and being (ontology). ... This article is about the concept of abstraction in general. ... Socrates This article is about the ancient Greek philosopher, for all other uses see: Socrates (disambiguation) Socrates (June 4, 470 – May 7, 399 BC) (Greek Σωκράτης Sōkrátēs) was a Greek (Athenian) philosopher and one of the most important icons of the Western philosophical tradition. ...

Particulars might (or might not) be all individuals. At any rate, they are certainly all concrete--again, with the possible exception of abstract particulars (tropes). In metaphysics and statistics, the word individual, while sometimes meaning a person, more typically describes any numerically singular thing. ... This article is about the philosophical term . ... Another meaning of Trope is Jewish cantillation. ...

The fact of the matter is that all such terms are used by philosophers with a rough-and-ready idea of how they work. If there is confusion or lack of agreement about the specifics, that is a reflection of the fact that philosophers have many competing metaphysical theories that inform more precise, but idiosyncratic, accounts of the meanings of these terms. Hence, for example, for convenience in formulating a solution to the problem of universals, 'particular' can be pressed into service in describing the particular instance of redness of a particular apple--even though redness (being abstract) is precisely the sort of thing that is not supposed to be particular. See philosophical jargon. The problem of universals is a conventional term given to what is in fact a nest of intertwined problems, some within the domain of cognitive psychology, others within that of epistemology, still others within ontology. ... This article is about the concept of abstraction in general. ...