Doctors welcome First Aid for fractures (4)
I believe the answer is:
gaps
'fractures' is the definition.
The answer and definition can be both acts as well as being plural nouns.
Maybe they are linked in a way I don't understand?
'doctors welcome first aid' is the wordplay.
'doctors' becomes 'gps' (GP is an example).
'welcome' is an insertion indicator (in sense of 'inviting in').
'first' indicates taking the first letters.
The first letter of 'aid' is 'a'.
'gps' going around 'a' is 'GAPS'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for gaps that I've seen before include "Breaks, spaces" , "Breaks or openings as in hedge or fence" .)