It’s a correlative conjunction
Let us review the definition of a conjunction. A conjunction is a word that connects or establishes a relationship between two or more words, phrases, or clauses.
Example: I ate the sandwich because I was hungry.
I ate the sandwich is an independent clause. I was hungry is also an independent clause. The word because is a conjunction connecting and showing a causal relationship between the two clauses.
When both is paired with and, they are known as a correlative conjunction.
A correlative conjunction is a pair of words that joins equivalent grammatical structures. Some correlative constructions are: both…and, either …or, neither …nor, not only….but also, whether …or.
The word both refers to two things or two actions or two persons. When you use both followed by and, you are telling the readers that you will identify or draw their attention to two things – first one thing and then the other.
Example: Both the kettle and the frying pan have bottoms made of copper.
In this sentence you can see that we referred to the kettle first and then to the second thing which is the frying pan.
You must have equivalent grammatical structures
Now let us look at another aspect of this correlative conjunction. It must join equivalent grammatical structures. This means that if the first item referred to is a noun then the second item must also be a noun. If the first item is a verb then the second item must also be a verb.
Example:
The hospitality students both cooked and served the meal.
Here you can see that equivalent grammatical structures are used with the correlative conjunction. A verb in the past tense “cooked”is used after both and similarly a verb in the past tense “served” is used after and.
Here is another example.
Both the team captain and the coach worked diligently to prepare the players for the match.
In this example the correlative conjunction is used with two nouns. Both is used with the noun “the team captain” while and is used with the noun “the coach”.
Look carefully at the sentence below.
The concert was both criticised by the newspapers and the radio stations.
This sentence is not correct. The correlative conjunction is not joining equivalent grammatical structures. Both is followed by a verb, while and is followed by a noun.
The correct sentence should be: The concert was criticised by both the newspapers and the radio stations.
That correction shows two nouns being linked by the correlative conjunction, both … and.
Put the word both in its correct position
You have to position the word both correctly to indicate what two things, or persons or actions are linked by the correlative conjunction.
Look at the sentence below.
I watched both the firing of the canon and the lowering of the flag at the sunset ceremony.
In this sentence both is placed before one event – the firing of the canon- so we expect that the other part of the conjunction, that is, the word and would be linking to another event in the same sentence. It does this by linking to – the lowering of the flag.
However if you position both in front of watched – I both watched the firing of the canon and the lowering of the flag at the sunset ceremony -you would have an incorrect sentence. You took one action. You watched. Now the reader expects you to link to another action that you took. However you took no other action. This means that you have put both in the wrong position in the sentence.
However if you intended to link two actions that you took then you have to include this second action. You can write for example – I both watched and photographed the firing of the canon and the lowering of the flag at the sunset ceremony. This demonstrates that you are linking watched and photographed.
You can also determine the correct position of both by checking to see whether the grammatical structure after both is the same grammatical structure that you have after and.
These tips should give you the confidence to use correctly the construction both… and.