Levels up at faculty (6)
I believe the answer is:
strata
'levels' is the definition.
(I know this)
'up at faculty' is the wordplay.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'faculty' becomes 'arts' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'at'+'arts'='atarts'
'atarts' in reverse letter order is 'STRATA'.
Can you help me to learn more?
(Other definitions for strata that I've seen before include "Layers or thicknesses of earth" , "Tiers of thicknesses" , "Layers of rock on earth's surface" , "bands" , "levels of society" .)