For hours, Mom, quite rudely, was kept in the dark (8)
I believe the answer is:
mushroom
'the dark' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'for hours mom quite rudely was kept' is the wordplay.
'hours mom' anagrams to 'MUSHROOM'.
However, I am not clear how this is indicated.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for mushroom that I've seen before include "Fleshy fungus" , "Food fungus" , "grow quickly" , "Grow very fast" , "grow suddenly" .)