However, many mass nouns in English can be converted to count nouns, which can then be used in the plural to denote (for instance) more than one instance or variety of a certain sort of entity – for example, "Many cleaning agents today are technically not soaps [i.e. types of soap], but detergents," or "I drank about three beers [i.e. bottles or glasses of beer]".
For example, the same set of chairs can be referred to as "seven chairs" (count) and as "furniture" (mass); the Middle English mass noun pease has become the count noun pea by morphological reanalysis; "vegetables" are a plural count form, while the British English slang synonym "veg" is a mass noun.
The work of logicians like Godehard Link and Manfred Krifka established that the mass/count distinction can be given a precise, mathematical definition in terms of quantization and cumulativity.
The expression "chairs", however, does, suggesting that the generalization is not actually specific to the mass-count distinction.
Notice again that this is probably not a fact about mass-count syntax, but about prototypical examples, since many singular count nouns have referents whose proper parts can be described by the same term.
Examples include divisible count nouns like "rope", "string", "stone", "tile", etc.
However, as noted above, such a characterization fails to explain many central phenomena of the mass-count distinction.
However, this may confuse syntax and semantics, by presupposing that words which denote substances are mass nouns by default.
[7] Nouns differ in the extent to which they can be used flexibly, depending largely on their meanings and the context of use.
However, suppletive use of less and least with count nouns is common in many contexts, some of which attract criticism as nonstandard or low-prestige.
However, the term "collective noun" is often used to mean "mass noun" (even in some dictionaries) because users conflate two different kinds of verb number invariability: (a) that seen with mass nouns such as "water" or "furniture", with which only singular verb forms are used because the constituent matter is grammatically indivisible (although it may ["water"] or may not ["furniture"] be etically indivisible); and (b) that seen with collective nouns, which is the result of the metonymical shift between the group and its (both grammatically and etically) discrete constituents.
Some words, including "mathematics" and "physics", have developed true mass-noun senses despite having grown from count-noun roots.