What could fasten loose cover back on stool (6)
I believe the answer is:
velcro
'what could fasten' is the definition.
I can't tell whether this definition defines the answer.
'loose cover back on stool' is the wordplay.
'loose' indicates anagramming the letters (letters are loosened from their original positions).
'back on' indicates one should take the final letters (the letter at the back).
The last letter of 'stool' is 'l'.
'cover'+'l'='coverl'
'coverl' with letters rearranged gives 'VELCRO'.
Can you help me to learn more?
(Other definitions for velcro that I've seen before include "Fastener for clothes with two strips pressed together" , "Sticky material - clover (anag)" , "In clover with cloth fastener" , "It fastens" , "Modern cloth fastener with two strips pressed together" .)