Like a point to concentrate on (5)
I believe the answer is:
focal
'on' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for focal that I've seen before include "sort of length" , "Of the point of convergence" , "Relating to a central point of interest" , "Things are concentrated at such a point" , "and 21 Across: Centre of attraction" .)