Australian turning over journal, Year in Science (7)
I believe the answer is:
zoology
'science' is the definition.
(zoology is a kind of science)
'australian turning over journal year in' is the wordplay.
'australian' becomes 'Oz' (nickname for Australia).
'turning over' shows that the letters should be reversed in order.
'journal' becomes 'log' (log can mean a journal or diary).
'year' becomes 'oy' (I am not sure about this - if you are sure you should believe this answer much more).
'in' means one lot of letters goes inside another.
'oz' written backwards gives 'zo'.
'log' put within 'oy' is 'ology'.
'zo'+'ology'='ZOOLOGY'
Can you help me to learn more?
(Other definitions for zoology that I've seen before include "Animal study" , "Science of animals" , "Science of animal life" , "The scientific study of animals" .)