Several? Yes, ten! (3)
I believe the answer is:
six
'several? yes ten' is the definition.
The answer and definition can be both quantities as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'yes ten' is the wordplay.
'yes' becomes 'si' (I can't justify this - if you can you should believe this answer much more).
'ten' becomes 'x' ('X' can be a synonym of 'ten').
'si'+'x'='SIX'
Can you help me to learn more?
(Other definitions for six that I've seen before include "Airborne boundary hit" , "Number of US moon landings" , "Number of bowls in a cricket over" , "VI" , "Half-dozen" .)