micronutrient

[noun]

Nutrients that are needed to grow and reproduce, but in small amounts. For example, plants need boron in order to develop fruits and seeds. However, the amount of boron needed to perform this function is much less than the amount of nitrogen the plant needs to perform photosynthesis. In humans, supplements generally labeled as vitamins fall into the micronutrient category. See also: limiting nutrient and macronutrient.