One of eight kings acquiring room regularly for bird sanctuary (7)
I believe the answer is:
heronry
'bird sanctuary' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'one of eight kings acquiring room regularly' is the wordplay.
'one of eight kings' becomes 'henry' (I've seen this in another clue).
'acquiring' means one lot of letters goes inside another.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternate letters of 'room' are 'ro'.
'henry' going around 'ro' is 'HERONRY'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for heronry that I've seen before include "colony with large bills" , "lot of long-legged chicks here" , "bird colony" , "Place for waders" , "Colony of large birds" .)