Rationale shown in the record, I see (5)
I believe the answer is:
logic
'rationale' is the definition.
(I've seen this in another clue)
'the record i see' is the wordplay.
'the record' becomes 'log' (log is a kind of record).
'see' becomes 'C' (the word for the letter, according to Chambers).
'log'+'i'+'c'='LOGIC'
'shown in' acts as a link.
(Other definitions for logic that I've seen before include "Aristotelian theories" , "Reasoned thinking" , "this makes sense" , "using premises" , "Science of correct reasoning" .)