Employer Identification Number
An EIN, or Employer Identification Number, is like a special number that the government gives to a business so it can be identified. It's a bit like how every person has a Social Security Number. Businesses use this number when they need to do official things like pay taxes, hire people, or open a bank account. It helps the IRS (the tax people in the United States) keep track of the business's tax reports and stuff like that.