Oratory from HCE and ALP enigmatical (6)
I believe the answer is:
chapel
'oratory' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for chapel that I've seen before include "Part of or alternative to church" , "NUJ members?" , "Nonconformist church" , "Perhaps part of cathedral" , "union group" .)