If you are writing a report for school, you are probably relying on a few references, or sources, for information. Or, if you are applying for a job, you may count on a reference from a previous boss to help you get the job.
Good references are sometimes necessary to either get a job or to get a job done well. A reference is someone you can rely on to put in a good word for you when applying for a job. Or, a reference might be an outside source you use in a research paper. Don't forget: if you reference outside work, be sure to mention it in your bibliography or "list of references" so you don't get accused of plagiarism. Give credit where it's due.