Facts about island’s earliest broadcast (9)
I believe the answer is:
realities
'facts' is the definition.
The answer and definition can be both related to thinking as well as being plural nouns.
Perhaps you can see an association between them that I don't see?
'about island's earliest broadcast' is the wordplay.
'about' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'broadcast' indicates anagramming the letters (letters scattered or cast around).
'earliest' anagrammed gives 'realites'.
'i' put into 'realites' is 'REALITIES'.
Can you help me to learn more?
(Other definitions for realities that I've seen before include "multiple universes" , "The facts of life" .)