noun, plural: micronutrients
A nutrient needed in small amounts
Micronutrients are those nutrients needed in small amounts as opposed to macronutrients required in large amounts. For example, proteins, vitamins, and minerals are nutrients humans need; however, proteins are needed in amounts higher than vitamins, making the latter considered as micronutrient. Although micronutrients are needed in small amounts they are crucial in normal and healthy condition of an organism.
Word origin: micro- (small) + nutrient