They are different classification systems for nouns. ) abstract nouns are uncountable, that is all. examples of mass nouns: bread, spaghetti, work examples of abstract nouns: advice , courage , freedom, knowledge, luck Wikipedia's simple definition for the different systems: A mass noun or uncountable noun is a noun with the syntactic property that any quantity of it is treated as an undifferentiated unit, rather than as something with discrete subsets.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.