Understood about the grade (8)
I believe the answer is:
gathered
'understood' is the definition.
('gather' can be a synonym of 'understand')
'about the grade' is the wordplay.
'about' is an anagram indicator.
'the'+'grade'='thegrade'
'thegrade' anagrammed gives 'GATHERED'.
(Other definitions for gathered that I've seen before include "The grade (anag.)" , "Brought together in one place" , "Collected - inferred" , "Collected or assembled together" , "Gleaned" .)