Meaning

noun the whole amount

noun material such as sand or gravel used with cement and water to make concrete, mortar, or plaster

noun a sum total of many heterogenous things taken together

originFrom Middle English aggregat(e) (“a sum, unit, complex, aggregate”), borrowed from New Latin aggregātum (“an aggregate”), substantivized from the nominative neuter singular of aggregātus, the perfect passive participle of aggregō (“to flock together”), from ad- (“at, to, toward”)) + gregō (“to flock or group”), from grex (“flock”, greg- in compounds) + -ō (verb-forming suffix). See also egregious…

Etymology from Wiktionary, CC BY-SA 3.0