Dynasty of kings and queens? It could collapse (5,2,5)
I believe the answer is:
house of cards
'dynasty' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for house of cards that I've seen before include "Unstable scheme" , "building that might fall over" , "Flimsy structure" .)