UK:*UK and possibly other pronunciationsUK and possibly other pronunciations/ˈbəʊθ/US:USA pronunciation: IPA and respellingUSA pronuncation: IPA/boʊθ/ ,USA pronunciation: respelling(bōth)

WordReference Collins English Usage © 2020
used for emphasis
When you link two phrases using and, you can put both in front of the first phrase for emphasis. For example, if you want to emphasize that what you are saying is true of two things or people, you put both in front of the first of two noun phrases.
By that time both Robin and Drew were overseas.
Both she and the baby were completely safe.
They felt both anxiety and joy.
These changes will affect both teachers and students.
Similarly you can put both in front of the first of two adjectives, verb phrases, or adverbials.
Herbs are both beautiful and useful.
These headlines both worried and annoyed him.
She has won prizes both here and abroad.
The phrase after both should be of the same type as the phrase after and. For example, you say ‘I told both Richard and George’. Don't say ‘I both told Richard and George’.
used with one noun phrase
You can put both immediately in front of a single noun phrase when it refers to two people or things. For example, you can say ‘Both boys were Hungarian’. You can also say ‘Both the boys were Hungarian’ or ‘Both of the boys were Hungarian’. There is no difference in meaning.
Be careful
Don't say ‘Both of boys were Hungarian’ or ‘The both boys were Hungarian’. Also, don't use ‘two’ after both. Don't say ‘Both the two boys were Hungarian’.
You can use either both or both of in front of noun phrases beginning with these, those, or a possessive determiner.
The answer to both these questions is ‘yes’.
I've got both of their addresses.
In front of personal pronouns you must use both of, not ‘both’.
Are both of you ready?
Don't use ‘we’ or ‘they’ after both of. Instead you use us or them.
Both of us went to Balliol College, Oxford.
Both of them arrived late.
used after the subject
Both can also be used after the subject of a sentence. For example, instead of saying ‘Both my sisters came’, you can say ‘My sisters both came’.
When there is no auxiliary verb, both goes in front of the verb, unless the verb is be.
They both got into the boat.
If the verb is be, both goes after be.
They were both schoolteachers.
If there is an auxiliary verb, you put both after it.
They have both had a good sleep.
If there is more than one auxiliary verb, you put both after the first one.
They will both be sent to prison.
Both can also come after a personal pronoun that is the direct or indirect object of the verb.
Rishi is coming to see us both next week.
negative sentences
You don't usually use ‘both’ in negative sentences. For example, don't say ‘Both his students were not there’. You say ‘Neither of his students was there’.
➜ See neither
Similarly, don't say ‘I didn’t see both of them'. You say ‘I didn’t see either of them'.
➜ See either
used as a pronoun
Both can also be a pronoun.
A child should eat either meat or eggs daily, preferably both.
Be careful
Don't use ‘both’ to talk about more than two things or people. Instead you use all.
➜ See all
'both' also found in these entries:

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