Everything under the sun I ever recollected (8)
I believe the answer is:
universe
'everything' is the definition.
(everything in the universe)
'under the sun i ever recollected' is the wordplay.
'under' says to put letters next to each other.
'recollected' is an anagram indicator (letters recollected and rearranged).
'sun'+'i'='suni'
'suni'+'ever' is 'suniever'.
'suniever' anagrammed gives 'UNIVERSE'.
(Other definitions for universe that I've seen before include "Sphere of thought" , "Cosmos" , "mind-boggling concept" , "sphere of activity" , "The whole world" .)