From Wiki

Many applications for entry to Canada allow adult applicants to include their dependent children on their appliations.

In most of these applications, the definition of a dependent child is as follows:

A son or daughter is dependent when the child:

• is under the age of 22 and does not have a spouse or common-law partner;
• is over the age of 22 and has been continuously enrolled as a full-time student and depended substantially on the financial support of a parent since before the age of 22;
• became a spouse or a common-law partner before the age of 22 and has been continuously enrolled as a full-time student and depended substantially on the financial support of a parent since becoming a spouse or common-law partner, or
• is over the age of 22 and depended substantially on the financial support of a parent since before the age of 22 because of a physical or mental condition.