RDA (recommended dietary allowance) is a recommended amount of a daily nutrient that is sufficient to meet the needs of 97-98% of the population. You can see your RDA’s here, which vary by age and sex.
When we don’t yet know enough to determine the RDA, you may sometimes hear the term AI (adequate intake). Yet another term you might hear is Dietary Reference Intakes (DRI’s) which is a general term that is used when referencing the RDA’s and AI’s together.
To make sure you are eating an adequate amount of nutrients, always fill half-your-plate at meal times with fruits and vegetables.