The Illuminati is a very close secret fraternity. According to Wikipedia, the Illuminati comes from the Latin Illuminatus, which means enlightened, is the name given to the ancient secret fraternal organization that ever existed and is believed to still exist today, even though there is no real evidence of the existence of this brotherly organization.

Adam Weishaupt (1748–1830), founder of the Bavarian Illuminati. The Illuminati (plural of Latin illuminatus, "enlightened") is a name given to several groups, both real and fictitious. Historically, the name usually refers to the Bavarian Illuminati, an Enlightenment-era secret society founded on 1 May 1776. The society's goals were to oppose superstition, obscurantism, religious influence over public life, and abuses of state power. "The order of the day," they wrote in their general statutes, "is to put an end to the machinations of the purveyors of injustice, to control them without dominating them."The Illuminati—along with Freemasonry and other secret societies—were outlawed through edict by the Bavarian ruler Charles Theodore with the encouragement of the Catholic Church, in 1784, 1785, 1787, and 1790.[2] In the several years following, the group was vilified by conservative and religious critics who claimed that they continued underground and were responsible for the French Revolution. https://en.wikipedia.org/wiki/Illuminati" - ikipedia source

Historically, the Illuminati name refers to the Illuminati of Bavaria, which is a secret group in the enlightenment era in Europe which was founded on May 1, 1776 AD in Ingolstadt (Upper Bavaria) with the name of the Illuminati Order. The initial members were five people and pioneered Adam Weishaupt, a Jewish descendant who was born and raised in Ingolstadt and has an educational background as a Jesuit.