NO. Soup is not a meal.
Soup is a course to a meal because soup is not really filling and won't feel you up like other foods would.
However eating only soup would be much better than eating nothing at all.
For example if you have a sore throat, stomach ache, the flu or a cold and don't feel like eating anything else then soup would be a good food to eat.
The soup would keep you full enough to at least prevent you from starving.
But when you're not sick then you should eat other things when you have your meal and eat the soup along with your other meal.
So for example you could eat a sandwich, hamburger, fries, potatoes, mashed potatoes, steak etc or eat a salad and then eat the soup.
But for a meal you need additional foods added to the meal to go along with the soup.
But soup is also a good food to eat strictly when you're on a weight loss diet because the soup will keep you full enough to where you won't eat other foods so the soup can help you lose some weight.