For tax purposes an eligible dependant is a very specific (and quite large) deduction. You should list all your children in the dependant section, but you can only claim one as an eligible dependant.
Just because you have a child does not mean that you can claim the eligible dependant amount. You cannot claim this amount for someone who was only visiting you.
Your dependant may live away from home while attending school. If the dependant ordinarily lived with you when not in school, we consider that dependant to live with you for the purposes of this amount.
For the purposes of this claim, your child is not required to have lived in Canada but still must have lived with you. This would be possible, for example, if you were a deemed resident living in another country with your child.