A business is a commercial enterprise carried on for the purpose of profit. This does not exclude businesses that are not currently generating profits or professional practices, but it does exclude governmental organizations, not-for-profit organizations, and others.
You can go back as far as five years before the date of your application (and up until a decision is made on your application by a visa officer).
To meet the definition, you must have at least two years of business experience and demonstrate a legally obtained net worth of at least CAN$300,000. You must then obtain a minimum of 35 points in a designed to determine whether you will be able to become economically established in Canada.
You will be required to indicate in writing that you have the intention and ability to meet given business conditions in Canada. After taking up permanent residence in Canada, you will have three years to meet these conditions.