[…] The manner how speech serveth to the remembrance of the consequence of causes and effects consisteth in the imposing of names, and the connexion of them.
Of names, some are proper, and singular to one only thing; as Peter, John, this man, this tree: and some are common to many things; as man, horse, tree; every of which, though but one name, is nevertheless the name of diverse particular things; in respect of all which together, it is called a universal, there being nothing in the world universal but names; for the things named are every one of them individual and singular. […]
Quotation from Thomas Hobbes – Leviathan. Chapter 4.