Multi-word lexical units are similar to compounds. A multi-word unit is a lexicalized sequence of words that functions as a single grammatical word. An example of such a lexical unit is the sequence SORT OF, which consists of two orthographic words, but they must be used together and in this exact order. Just like with compounds, there are only limited possibilities of substitution.
The meaning of a multi-word lexical unit is often unpredictable. It’s not the sum of the meanings of the components. The meaning is assigned to the whole unit and the unit can’t be further analyzed semantically. Such units are referred to as idioms. For example the idiom ONCE IN A BLUE MOON simply means SELDOM, which is not so obvious if you consider the meanings of all the words it consists of.
Commonly Recognized Types of Units
Within the set of multi-word units we have the following groups of words:
– phrasal verbs: TURN IN (= go to bed)
– prepositional verbs: CARE FOR (= look after)
– complex prepositions: ACCORDING TO
– complex subordinators: AS SOON AS
– correlative coordinators: EITHER…OR
– inserts: THANK YOU
Each of these groups deserves an article of their own, but for now there’s just one example of each so that you have a general idea what it’s all about.
Multi-Word Units vs Collocations
Multi-word lexical units should be also distinguished from collocations. The latter consist of independent words used together, but still separable without losing its main sense. For example BONE DRY is a collocation, so if you just say DRY, the general idea is the same. Here one word only intensifies the other, but the meaning of BONE DRY is not completely different from the meaning of DRY.
In case of a multi-word unit such as GIVE UP for example, which is a phrasal verb by the way, if you remove one of the words, the meaning will be different or it won’t make any sense at all. Have a look:
He GAVE UP smoking.
This sentence makes sense. But if you remove either word, it will no longer make sense.
Here’s a video version of this article: