Thanks for the information folks

My plan is to apply for single entry visa to canada from usa and than go to nepal and travel canada from there. I m concerned if I have to enter from USA or if i can fly canada from Nepal. I am not looking to travel multiple times one time is good enough for me. My common sense also says I should be able to fly canada one time from anywhere of the world but just confirming. Any more ideas still welcome. thanks a lot folks