What is a partitive noun?

Answer 1

There are two kinds of nouns in English, "for stuff and things."

Nouns for things can have the word "a" in front of them: "A cat" or "a stick" or even an abstraction like "a democracy." The implicit model is that what you are talking about is separate and comes with its own boundaries. The cat has a skin, the stick has its bark, the democracy has its borders. If you use "some" with a thing-noun, the noun must be plural: "Some cats, some sticks, some democracies."

Nouns for stuff cannot have the word "a" in front of them. The implicit model is of a continuous, unboundaried substance. If you want a finite amount of it, you must bring your own container: "a cup of water, a stick of butter, a yard of wire." If you use "some" with these nouns, the noun can be singular: "go to the store and get me some water, some butter and some wire, OK?" Stuff nouns don't have plural forms. "Partitive nouns" is the grammatical term for stuff-nouns.

There are two things that make this distinction confusing:

1) There is no visible or audible clue which category a noun belongs to. You just have to see what a native speaker of English says.

2) Some nouns belong to both categories, with subtly different meanings. "Some wire" suggests unbounded wire - maybe a big spool, or wire whose ends are not yet found. "A wire" implies a cut and bounded piece of wire, say connecting two points. "Some water" implies water without firm boundaries. "A water" might be a variety of water (a clerk offers you a plastic bottle and says "A remarkable water.") or a bounded water-area ("Ships were in the boundary waters.")