Much is used with uncountable nouns to talk about a large amount of something, like time, money, or water. It can also be used as an adverb meaning “to a great degree,” as in “much better.”
From Old English *mycel* or *micel* “great, large,” related to German *viel* and Dutch *veel* “much, many.” Over time its form and use narrowed to focus on quantity and degree, especially with uncountable nouns.
English splits quantity into a little system: *much* for uncountable (much water), *many* for countable (many bottles), and *a lot* as a kind of universal shortcut. Native speakers follow this system without thinking, but learners can hack it by asking: “Can I count it one-by-one?” If yes, use *many*; if not, use *much*.
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