Court case finishing early – detectives upset regarding collection of notes (7)

I believe the answer is:
triadic
'court case finishing early detectives upset regarding collection of notes' is the definition.
I can't judge whether this definition defines the answer.
'court case finishing early detectives upset' is the wordplay.
'court case' becomes 'trial' (a trial in court).
'finishing early' means to remove the last letter (the word finishes earlier than normal).
'detectives' becomes 'CID' (abbreviation for Criminal Investigation Department).
'upset' is a reversal indicator.
'cid' written backwards gives 'dic'.
'trial' with its final letter removed is 'tria'.
'tria'+'dic'='TRIADIC'
Can you help me to learn more?
(Other definitions for triadic that I've seen before include "In threes" , "of secret society" , "Of a set of three" , "Relating to a group of three" , "Concerning a group of three" .)
