Acceleration in racing, by the way (5)
I believe the answer is:
speed
This could be a double definition.
'acceleration in racing' is the first definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'way' is the second definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'by the' is the link.
Can you help me to learn more?
(Other definitions for speed that I've seen before include "Tempo - drug" , "Swiftness" , "Rapidity - amphetamine" , "Pace or tempo" , "Rapidity of movement" .)