Cheer at unorthodox tract (7)

I believe the answer is:
hectare
'tract' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'cheer at unorthodox' is the wordplay.
'unorthodox' indicates anagramming the letters.
'cheer'+'at'='cheerat'
'cheerat' with letters rearranged gives 'HECTARE'.
Can you help me to learn more?
(Other definitions for hectare that I've seen before include "10,000 squaer metres" , "Some land in France" , "Metric measure of area" , "10,000 square metres" , "Amount of ground" .)
