Meaning

adjective too numerous to be counted

noun a large indefinite number

noun the cardinal number that is the product of ten and one thousand

originFrom French myriade, from Late Latin mȳriadem (accusative of mȳrias), from Ancient Greek μυριάς (muriás, “number of 10,000”), from μυρίος (muríos, “numberless, countless, infinite”). By surface analysis, myria- + -ad.

Etymology from Wiktionary, CC BY-SA 3.0