Print media admitting certain stresses (9)

I believe the answer is:

pressures

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'stresses' is the definition.
The answer and definition can be both acts as well as being plural nouns.
Maybe there's an association between them I don't understand?

'print media admitting certain' is the wordplay.
'print media' becomes 'press' (press is a kind of print media).
'admitting' means one lot of letters goes inside another (admit can mean to welcome in or accept).
'certain' becomes 'sure' (synonyms).
'press' enclosing 'sure' is 'PRESSURES'.

Can you help me to learn more?

I've seen this clue in The Guardian.

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