Guinness head on a number of beers from the bar arena (6)
I believe the answer is:
ground
'beers from the bar arena' is the definition.
'ground' can be an answer for 'arena' (I've seen this before). I'm unsure of the 'beers from the bar' bit.
'guinness head on a number' is the wordplay.
'head' indicates taking the first letters.
'on' says to put letters next to each other.
'a number' becomes 'round' (I have seen 'number of drinks' mean 'round' so perhaps 'number' could also mean 'round'**).
The initial letter of 'guinness' is 'g'.
'g'+'round'='GROUND'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for ground that I've seen before include "Oval, for example" , "See 14" , "Solid part of the earth's surface" , "Earth; stop from flying" , "Land; reduced to powder" .)