Main meal = breakfast or lunch or dinner. Only one is the "main meal". Main course = the part of any meal which is the "main part". Dinner might be soup and salad and dessert, and the "main course" is a plate that has steak and lobster.

The article is not using the term "main meal" correctly. It should be written as "main course".

Thank you very much for your patient response. Does 'Main meal' in this article mean the same thing as 'main course'? I'm quite confused about it.

Main meal means the most important meal of the day. Depending on your culture, the main meal could be dinner but in other cultures the main meal might be lunch. Main course is the largest or most important dish in a meal. For example the main course for a Thanksgiving lunch is usually the Turkey.