Stays to enclose a number in some armour (7)

I believe the answer is:

corslet

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'armour' is the definition.
(I know that corslet is a type of body armor)

'stays to enclose a number' is the wordplay.
'stays' becomes 'corset' (stays can refer to a corset).
'to enclose' indicates putting letters inside.
'a number' becomes 'L' (fifty in Roman numerals).
'corset' enclosing 'l' is 'CORSLET'.

'in some' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Another definition for corslet that I've seen is " Piece of armour".)

I've seen this clue in The Globe and Mail.

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