nominalism, in philosophy, a theory of the relation between universals and particulars. Nominalism gained its name in the Middle Ages, when it was contrasted with realism. The problem arises because in order to perceive a particular object as being of a certain kind, say a table, we must have a prior notion of table. Does the kind "table," described by this prior notion, then have an existence independent of particular tables? Nominalism says that it does not, that it is just a name for a group of particular objects. Nominalism is appropriate to materialist and empirical philosophy and hence has been popular in modern thought.
See R. A. Eberle, Nominalistic Systems (1970).