A great thing to put first into a stocking (3,3)
I believe the answer is:
big toe
'a stocking' is the definition.
Both the definition and answer are singular nouns.
Perhaps there's an association between them I don't understand?
'a great thing to put first' is the wordplay.
'a great' becomes 'big' (I've seen this in another clue).
'thing' becomes 'e' (I am not sure about this - if you are sure you should believe this answer much more).
'put first' is a charade indicator (letters next to each other).
'e' put after 'to' is 'toe'.
'big'+'toe'='BIG TOE'
'into' is the link.
Can you help me to learn more?
(Other definitions for big toe that I've seen before include "Largest foot digit" , "Largest pedal extremity" , "Corn grows here" , "that once went to market?" , "member of the body" .)