One of seven, for example, grabbing a stool (8)
I believe the answer is:
saturday
'one of seven' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'for example grabbing a stool' is the wordplay.
'for example' becomes 'say' ('say' can be used to introduce an example).
'grabbing' indicates putting letters inside.
'stool' becomes 'turd' (turd is a kind of stool).
'a'+'turd'='aturd'
'say' enclosing 'aturd' is 'SATURDAY'.
Can you help me to learn more?
(Other definitions for saturday that I've seen before include "when many are out of work" , "Ian McEwan novel about day of the week" , "24 hours" , "Jewish Sabbath" , "Part of the weekend" .)