Lower a rail so diverted underneath church (9)
I believe the answer is:
charolais
'lower' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'a rail so diverted underneath church' is the wordplay.
'diverted' indicates an anagram (each letter get diverted elsewhere).
'underneath' says to put letters next to each other (in a down clue, some letters go under others).
'church' becomes 'ch' (common abbreviation).
'rail'+'so'='railso'
'railso' anagrammed gives 'rolais'.
'a'+'rolais'='arolais'
'arolais' after 'ch' is 'CHAROLAIS'.
Can you help me to learn more?
(Other definitions for charolais that I've seen before include "White beef-cattle" , "White breed of beef cattle" , "Provider of beef" , "beast" .)