Full Idea
'Nominalism' is distinct from 'extensionalism'. The main point of the latter doctrine is rejection of properties or attributes in favour of classes. But class are universals equally with attributes, and nominalism in the defined sense rejects both.
Gist of Idea
Nominalism rejects both attributes and classes (where extensionalism accepts the classes)
Source
Willard Quine (Lecture on Nominalism [1946], §3)
Book Reference
'Oxford Studies in Metaphysics vol.4', ed/tr. Zimmerman,Dean W. [OUP 2008], p.8
A Reaction
Hence Quine soon settled on labelling himself as an 'extensionalist', leaving proper nominalism to Nelson Goodman. It is commonly observed that science massively refers to attributes, so they can't just be eliminated.