Basic report of three successive letters on time for each pupil (9)
I believe the answer is:
elemental
'basic' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for elemental that I've seen before include "key" , "Rising trend" , "of fire, say" , "radical" , "Nature spirit" .)