Torn piece of linen that can mean a clean sheet (3)
I believe the answer is:
nil
'can mean a clean sheet' is the definition.
I can't tell whether this defines the answer.
'torn piece of linen' is the wordplay.
'torn' becomes 'ni' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'piece of' indicates taking the first letters.
The first letter of 'linen' is 'l'.
'ni'+'l'='NIL'
'that' is the link.
Can you help me to learn more?
(Other definitions for nil that I've seen before include "Nothing, no score" , "There's nothing left" , "Zero, zilch" , "0" , "Lacking value" .)