A count noun, or countable noun, is a noun that can have a plural form. Other nouns, called uncountable nouns, can only have a singular form, where a greater amount is simply an extension of one undifferentiated mass. Understanding the use of the count noun vs. the uncountable noun is a major part of language learning for non-native English speakers, and a prominent element of English grammar.
A popular way to illustrate countable and uncountable nouns is through a simple grocery list. Here, it becomes evident that some items, which are evaluated in numerical quantities, can easily take the plural, and others, which are undifferentiated masses, cannot. For example, consider the following items: eggs, milk, oranges, tea, butter and crackers. Readers can separate the two types of nouns into two derivative lists. The first list consisting of count noun examples will include eggs, oranges, and crackers; the other list will include milk, tea and butter.
It's interesting to note that in some cases, the use of uncountable nouns is not exclusive to a noun, which generally has an undefined mass, and the use of a count noun may apply in some strange instances. For example, in the use of the word "waters," often taken from a translation of an archaic reference, the noun, which is generally uncountable, is switched to a count noun, although no numerical label is applied. For instance, even though a writer may refer to the "flowing waters" of an area, he or she will not normally enumerate using phrases like "two waters," "three waters;" note that in colloquial language "two waters" might refer to two glasses or portions of water.
Yet another way to look at count nouns is in the context of intangible, abstract nouns that represent ideas. Nouns like charity, hope, love, bliss, anger, and many other nouns connected to emotions or values are normally considered uncountable. By contrast, many of these same words may be used as count nouns to represent a collection of singular, contrasting, and/or conflicting ideas. For example, the word "emotion" is used as an uncountable noun when referring to an overall state of mind: "our conversation was filled with emotion." On the other hand, the same word may be used as a count noun when listing defined, unique categories: "The emotions of sadness and anger are often experienced together."
Using these two types of nouns appropriately is important in English grammar. One commonly noted challenge involves the use of quantitative modifiers. Some of these items include "many" and "few," which complement count nouns, and "much" and "little," which are used only with uncountable nouns.