Accurate reading misinterpreted then, tour crossing river (4,5)
I believe the answer is:
true north
'accurate reading' is the definition.
The definition suggests a singular noun which matches the answer.
'misinterpreted then tour crossing river' is the wordplay.
'misinterpreted' is an anagram indicator.
'crossing' is an insertion indicator (to cross can mean to go over or around).
'river' becomes 'r' (abbreviation for river).
'then'+'tour'='thentour'
'thentour' with letters rearranged gives 'truenoth'.
'truenoth' enclosing 'r' is 'TRUE NORTH'.
Can you help me to learn more?
(Other definitions for true north that I've seen before include "rarely needled when on the move" , "Position of maximum latitude" , "Pole" , "Direction aligned with earth's axis" , "In the direction of one of the poles" .)