The term "principal meal of the day" typically refers to the meal that is consumed in the middle of the day, often referred to as lunch. However, there are several other words and phrases that can be used to describe this important meal. For example, it can also be referred to as the primary meal of the day, the main meal, the midday meal, or the noon meal. Additionally, in certain cultures or regions, there may be unique terms used to describe this meal, such as siesta in Spain or fika in Sweden. Regardless of what it is called, the principal meal of the day is an essential part of maintaining a healthy diet and fulfilling daily nutritional needs.