Difference among Accounting & Accountancy

hey guys ..
Today we have differ topic confuse people more than the other we treated last time however it's easiness .In public We found all branches of science have official name is called with it for example :Chemistry , mathematics , Social studies etc.but here in this area we find more than one name we can called our field as Accounting or Accountancy ...why ? why there are more one name for this science ?Accountants eventually set up definitions for this two terms,to stop the chaos that was caused by them ..
Accountancy : It's the main science with it's all theoretical concepts,fundamentals,principles,manners and systems of recording.That's mean (The theoretical face of this science)
On the other hand :
Accounting : It's The practical manner of all theoretical points, major inrecording , analyzing financial transaction(business deal involving money) and auditing , detailed financial statement(record of financial transaction during a specified period) .. That's mean the continuous responsibilities of recording transaction (The practical face of the science.)So mostly we can call this science with it's practical name as it's the more usage in business life.
best hopes,
Mostafa