Short answers, pulled from the story.
Mass nouns are terms where any part or quantity is treated as an undifferentiated unit rather than discrete elements. This behavior defines how words like water flow through a sentence without counting.
English speakers cannot directly modify such words with numerals like one, two, or three without adding a measurement unit first. A speaker might say 20 litres of water but never 20 waters in standard usage.
The comparative forms fewer and less show historical divergence dating back to 1770. Criticism of using less with count nouns ignores that usage dates back to Old English.
Logician Manfred Krifka established mathematical definitions for the mass-count distinction through quantization and cumulativity. Godehard Link contributed similar frameworks to this semantic analysis.
Names of animals such as chicken or fox function as count nouns when referring to living creatures but mass nouns for meat or fur. Fire acts frequently as a mass noun yet a fire denotes a discrete entity.