Who dared to change a dictionary entry? (8)

I believe the answer is:

headword

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'a dictionary entry?' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?

'who dared to change' is the wordplay.
'to change' indicates anagramming the letters.
'who'+'dared'='whodared'
'whodared' anagrammed gives 'HEADWORD'.

Can you help me to learn more?

I've seen this clue in The Independent.

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