Macronutrients are nutrients required by plants in large quantities, typically measured in grams per kilogram of plant dry weight. These include nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. Micronutrients, on the other hand, are required in smaller quantities, typically measured in parts per million (ppm) or even parts per billion (ppb). These include iron, manganese, zinc, copper, boron, molybdenum, and chlorine.

You answered your question. Macronutrients are elements which plants require in relatively large amounts, whereas micronutrients are those which plants require in much smaller amounts :)

The three main macronutrients are Nitrogen (N: The plant takes up nitrogen in the form of nitrate.).potassium (P: involved in root growth, flowering stage e.t favors flowering etc), and phosphorus (K: It boosts cell tissue strength, boosts photosynthesis, and turns on nitrate absorption.)

There are 7 essential plant nutrient elements defined as micronutrients boron, zinc, manganese, iron, copper, molybdenum, chlorine required in smaller quantities