One of two rugby players positioned either side of the hooker in a scrum (4)
I believe the answer is:
prop
'one of two rugby players positioned either side of' is the definition.
I can't tell whether this defines the answer.
'hooker in a scrum' is the wordplay.
'hooker' becomes 'pro' (I've seen this before).
'in a scrum' becomes 'p' (I can't explain this - if you can you should believe this answer much more).
'pro'+'p'='PROP'
'the' is the link.
Can you help me to learn more?
(Other definitions for prop that I've seen before include "Person or thing providing support" , "Support; rugby forward" , "Object used on the set of a play" , "Temporary support" , "Stay" .)