Annual celebration of motherhood? (6,3)
I believe the answer is:
labour day
This clue might be a double definition.
'annual celebration' is the first definition.
The definition suggests a singular noun which matches the answer.
'motherhood?' is the second definition.
Both the answer and definition are singular nouns.
Perhaps you can see a link between them that I don't see?
'of' acts as a link.
Can you help me to learn more?
(Other definitions for labour day that I've seen before include "May start" , "when delivery is expected?" .)