Throw light on up in Montrose (4)
I believe the answer is:
sort
'throw light' is the definition.
'sort' can be an answer for 'throw' (thesaurus). I'm unsure of the 'light' bit.
'up in montrose' is the wordplay.
'up' is a reversal indicator (in down clue: letters go upwards).
'in' indicates the answer is hidden within the clue.
'tros' is hidden in the letters of 'montrose'.
'tros' reversed gives 'SORT'.
'on' acts as a link.
Can you help me to learn more?
(Other definitions for sort that I've seen before include "Type - arrange in groups" , "Put in order" , "Type, category" , "Kind, type or make" , "'Variety, type (4)'" .)