Some people think economy science is about saving money and investing in the best time and it is a misunderstanding. Saving money and investing relate to money management not economy science.

The definition of economy science is:
Economics (/ɛkəˈnɒmɪks, iːkə-/)is the social science that studies the production, distribution, and consumption of goods and services.
Wikipedia

Of course some scholars describe it in other ways too. For example they call it the science that studies the way governments and people expend money.
In general there is no definite deion of it.

Too many scientists have worked hard through the history and the economy science today is the result of their triumph.

Adam smith was one of the first economists. He believed the farms are not the most important. They are tools to work and earn money. He thought the work is more important than the farm.

He said everybody is after his own benefits. Bakers cook breads not because of customers but for himself. Customers buy bread not because of the bakers but for themselves and Adam smith founded the modern economy.