What does Acceptable daily intake mean?

Acceptable daily intake meaning in Medical Dictionary

Estimate of level of a substance in meals or drinking water, expressed on a body size basis (usually mg/kg weight), that can easily be ingested daily over an eternity by humans without appreciable wellness risk. For calculation of the everyday intake per person, a regular body mass of 60 kg can be used. The acceptable daily intake is normally useful for food additives (bearable daily intake is employed for pollutants). Abbreviated ADI.