Mass noun

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Mass nouns, also called uncountable nouns, name substances or wholes that you think of as a single thing rather than as separate items. Water, sand, air, sugar, wood, and furniture are common examples. Count nouns are the opposite: they name things you can count one by one, like chairs, apples, and cars.

How we talk about them
- With mass nouns, we usually need a unit when we measure: “20 liters of water,” “two cups of sugar.” We don’t say “twenty waters.”
- You can say “so much water” but not “so many water.”
- Mass nouns usually take a singular verb: “Water is essential.”

Some words can be mass or count nouns
- A word can be mass in one situation and count in another. For example, “There’s apple in the sauce” (apple as a substance) vs. “Three apples” (counting individual apples).
- “Paper” is a mass noun when we mean the material (three reams of paper), but a count noun when we mean individual sheets or essays (the students handed in their papers).
- “Cutlery” is generally mass, while “chairs” is count. “Furniture” is mass; “a piece of furniture” is a single item.

Other notes
- Some nouns are clearly mass (water, juice, sugar, metal, wood), and some are clearly count (chairs, cars, bottles). Many nouns can do both, depending on meaning.
- In English, a few nouns that name substances or groups of objects tend to be used in mass form, while those naming individual items are usually counted.
- Different languages handle mass and count in different ways. Some languages use measure words with mass nouns; others have other rules.

Quantifiers
- Some quantify both mass and count nouns (all, no, some, a lot of).
- Others pair with only one type: few and many go with count nouns; little and much go with mass nouns.
- Expressions like “a number of” and “a lot of” can be used with both.

Collective nouns and other quirks
- Collective nouns (group, committee) are usually treated like count nouns, not mass nouns.
- There are exceptions and nuances, and some words (like mathematics or physics) have mass-noun senses even though they come from other roots.

In short, mass nouns refer to substances or wholes seen as a single unit, require units for exact amounts, and can often be used in both mass and count ways depending on meaning.