Here is a great way to tell the difference between eating a meal or a snack.
All food breaks down into six different food groups. They are as follows: carbohydrates, protein, dairy, fruits, vegetables, and fats. The best way to ensure you have a balanced nutritional intake is to be sure you are eating three meals per day and about two snacks per day. A well-balanced MEAL contains at least one serving from at least three of the food groups. If you are only eating two food groups in a sitting (breakfast, lunch, or dinner), you are only consuming a SNACK. By following this little rule, you can better meet your nutritional needs for your micronutrients.
For example, if at breakfast, you have a bowl of whole-grain cereal with milk and a cup of black coffee that is a snack. If you add a piece of fruit or a handful of nuts, that will classify it as a meal.
Check out https://www.choosemyplate.gov/ten-tips-build-healthy-meal for tips on building healthy meals.