Observe in Croke Park or in court in America that involves a brief encounter
I believe the answer is:
witness stand
'croke park or in court in america that involves a brief encounter' is the definition.
I can't tell whether this defines the answer.
'observe in' is the wordplay.
'observe' becomes 'witness' (I've seen this before).
'in' becomes 'stand' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'witness'+'stand'='WITNESS-STAND'
Can you help me to learn more?
(Other definitions for witness stand that I've seen before include "Feature of US courts" , "Place in US courts" , "Where Americans testify" .)