Nouns that premodify other nouns

These two images both include examples of a noun ('crime') that premodifies another noun (crime agency / crimes unit). In one of them, 'crime' is in the singular, but in the other it is pluralised. 

Normally, when two nouns are placed next to each other like this so that the first noun premodifies the second one, that first noun is always placed in the singular form, even when it refers to more than one thing. I wrote about this some time ago in the post here.

Examples include:

• two dollar note (not two dollars note)
• three-person vehicle (not three-persons vehicle)
• Child fares available (not children fares available)

This rule applies even to nouns which are only normally used in the plural form in standard speech -- think of nouns like 'trousers' or 'scissors'. Oddly, when these pre-modify another noun, they become singular:

• trouser press [i.e. a device for pressing trousers]
• scissor sharpener [i.e. a device for sharpening scissors]

However, there are a few important exceptions to this rule. Consider this sentence:

• Has anyone seen my glasses case?

The expression 'glasses case' refers to a case that holds a person's glasses. You will notice that the noun 'glasses' here is in the plural form, not the singular as we have seen elsewhere. If even words like 'trousers' and 'scissors' are made singular when they pre-modify, why not 'glasses'?

The answer becomes clear when we see what happens if we do make the word singular:

• Has anyone seen my glass case?

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By changing 'glasses' to 'glass' we have changed the meaning of the word, from 'a device for seeing better' to 'something made of glass'. At the same time, we have changed the word from a countable noun to an uncountable one. To avoid this happening, we need to retain the original plural form 'glasses' in this expression.

Generally, if changing a plural noun to its singular form in a noun cluster will cause a significant change of meaning for that noun, then we retain the plural form. This situation most commonly arises with nouns that  have both countable and uncountable versions. When these nouns are in a premodifying position before another noun, it can sometimes be difficult to know whether their meaning is the countable or uncountable one.  

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A good example of this is the noun 'saving'. This can be used as a countable noun (usually found in the plural, 'savings', e.g. 'I withdrew all my savings from the bank'). 'Savings' in its countable form refers to the specific monetary assets that we have accumulated. However, the noun 'saving' can also be uncountable. 'Saving' as an uncountable noun refers to the act of accumulating assets, and not to the assets themselves. This is why you will see noun clusters such as 'savings bank' and 'savings account'. The countable noun 'savings' is retained in the plural in front of another noun to make it clear we are talking about physical assets; i.e. the bank is a bank that looks after peoples' (physical) savings, and the account is for your savings. If we used the expression 'Saving Bank' instead, it would be unclear which use of the word 'saving' we have in mind -- countable or uncountable?   

Another common example is the word 'sport', which can be both countable and uncountable:

• C -- a specific organised physical activity (Tennis is a sport, The students played many different sports)
• U -- the general non-specific category of all organised physical activities (Sport is an important part of youth education, We need to have more sport in the programme)

When the word is used to pre-modify another noun, you will often see it in the plural form in order to make it clear we are talking about specific individual activities:

• The school Sports Day includes 15 different sports. 
• Welcome to today's Sports News [i.e. a news broadcast that looks at many specific and individual sports]

This brings us to the signs with which we launched this post. You may have realised by now that the word 'crime' is another noun that can be used as both a countable noun (to refer to specific examples of illegal behaviour, e.g. robbery, arson, assault etc) and as an uncountable noun, to refer to all kinds of illegal behaviour generally (e.g. 'There is a lot of crime in Mong Kok'). If we want to use the noun 'crime' to premodify another noun (like 'unit'), we need to decide whether it is the countable or uncountable sense that applies to the unit. By placing the word 'crime' in the plural, the Microsoft Digital Crimes Unit is making it clear that the purpose of the unit is to handle specific individual examples of illegal digital behaviour (e.g. phishing, malware, identity theft etc). If 'crimes' was not placed in the plural (in accordance with the usual English rule described above), then most readers would assume that this was the uncountable form.

By contrast, the 'National Crime Agency' is clearly using the noun 'crime' as an uncountable noun here, and this name tells us that the purpose of the agency is to investigate and handle all kinds of illegal behaviour that occurs across the nation.