Mass Noun

A mass noun is a noun denoting something that cannot be counted (e.g., a substance or quality), in English usually a noun that lacks a plural in ordinary usage and is not used with the indefinite article.

The mass noun refers to a noun that cannot be counted in discrete units, but is rather treated as a single unit, no matter how much of it there is.

For example, if you tell your friend that you had "some beer" the previous evening, beer would be a mass noun in this context. On the other hand, if you said you had "three beers", then beer would not be a mass noun, since the beer could then be counted in discrete units. A synonym for the mass noun is the uncountable noun, which you can read more about here.

Correct usage

Here is an example of the mass noun being used correctly within a sentence. 

"When the patron of the restaurant fainted, the waiter yelled at the bartender to get him some water immediately."

In this sentence, the word water is a properly used mass noun. 

Now, here is an example of the incorrect use of the mass noun in a sentence. 

"The carpenter said that he needed special woods in order to fulfill the innovative design requested by his client." 

Woods should say wood to be a mass noun here, unless the carpenter is talking about more than one kind of special wood. This previous example is a general description - otherwise categorized as a common noun.

In case you still have some questions about the nature of the mass noun, here are a couple rules you can follow to make better sense of the concept:

1. Whenever the mass noun is used, it is not possible for you to imagine the object having discrete parts. For example, with the word "fire", you cannot imagine little particles or units of fire within the fire as such. This makes fire a mass noun within this context. 

2. Many nouns can have both mass noun and countable noun forms, depending on how they are expressed. For example, coffee is a mass noun in the phrase "some coffee" but a countable noun in the phrase "a coffee". Again, the main thing you need to do is determine whether you can imagine the noun in question as a discrete unit. 

Purpose of mass nouns and more clarification

The concept of the mass noun is related to the question of what people can and cannot ordinarily perceive as being a discrete unit. 

For example, many liquids and gases are often referred to by a mass noun, due to the simple fact that it is often difficult to perceive these substances as discrete units of some kind. Likewise, raw materials, such as wood, are also often designated by a mass noun, since the substance itself is not discrete when it is in an unformed state. On the other hand, human beings and other sentient creatures are often not designated by mass nouns, except for sociological or analytical purposes. 

It is important to understand that the mass noun is a construction of language, and not an inherent property of a given object itself.

For example, a given quantity of water could be described as "some water", or it could also be quantified as "x molecules of water". In the first case, water would be a mass noun, whereas in the second case, it would not. This shows that the difference inheres not to the actual substance water but rather to the language that is being used to describe the water.