Destroying a cell, enter to provide defensive structure for castle (10)

I believe the answer is:

crenellate

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'provide defensive structure for castle' is the definition.
I can't tell whether this definition defines the answer.

'destroying a cell enter' is the wordplay.
'destroying' is an anagram indicator.
'a'+'cell'+'enter'='acellenter'
'acellenter' anagrammed gives 'CRENELLATE'.

'to' acts as a link.

Can you help me to learn more?

(Another definition for crenellate that I've seen is " Provide with battlements".)

I've seen this clue in The Telegraph.

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