Electronic Data Gathering, Analysis and Retrieval - EDGAR
Edgar is a deformed giant that lives in the basement of the Treasury Department and survives on a diet of fish heads and leftover money-printing ink. If you don't pay your taxes, the IRS might lock you in a room with Edgar...or at least that's what the legends say.
EDGAR (in all caps) is an digital portal used by the SEC to give people access to filings from public companies. The letters, by the way, stand for "Electronic Data Gathering, Analysis, and Retrieval."
You run a company that trades its stock on a public exchange like the NYSE or NASDAQ. You have to make periodic filings with government regulators, especially the SEC. These documents let people know your finances, and include important disclosures, like when executives buy or sell company stock.
If a regular person wants to look at one of these documents, they can easily access a digital copy on the EDGAR website. Basically, instead of sticking all that paperwork into a filing cabinet in some dank D.C. basement, the SEC makes the digital copies available through EDGAR.