Time to turn the key I inserted in it (5)
I believe the answer is:
eight
'time' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'turn the key i inserted in it' is the wordplay.
I cannot really understand how this works, but
'turn' could be 't' (abbreviation in Oxford Dictionary of Abbreviations) and 't' is located in the answer.
'key' could be 'g' (musical key) and 'g' is found within the answer.
'i' is present in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is present in the answer.
A single letter 'h' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for eight that I've seen before include "destroyed [IN 8A] here!" , "Hit, e.g. (anag.)" , "1,001 - 993" , "4x2" , "Crew of racing shell" .)