Associations making line printing essentials (5)
I believe the answer is:
links
'associations' is the definition.
Although both the answer and definition are plural nouns, I don't see how they can define each other.
'line printing essentials' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'printing essentials' becomes 'inks' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'l'+'inks'='LINKS'
'making' acts as a link.
Can you help me to learn more?
(Other definitions for links that I've seen before include "Rings or loops of a chain" , "Type of golf course" , "Joins on the golf course?" , "Connects, ties in" , "Bits of chain" .)