Is that normal for having no pass motion for 2 to 3 days once a week?
Would it be categorized as a constipation?

Agree! my friends pass motion about 3 times a week, but try to think this way, if one only pass motion once a week, it is pretty abnormal as it may sound.
Where the hell the food go if you eat without defecate out daily? so sometimes, i think the condition of not passing motion daily may be abnormal as it may sound.

Agree but I still thinks that it's better to pass motion every single day. 

I know that each morning wake up drink a glass of water immediately before you brush your teeth, after that go sit on the toilet bowl for some time, practice every day and make it as a habit, you will eventually pass motion every day.

Stress and time constrain could also be the factor in pass motion difficulties.