A reliable source is something that is dependable. It is something that is recent and written by someone that is dependable. Such as a student from 1994 wouldn't neccasarily be a reliable source. Mainly because you don't know if any thing has changed since then, and you have NO idea where they got they're information. A dependable person is a Mayor, a Candidate (for president, senate, etc.), teacher, etc. If you know who the article is by and when it was written you more than likely know if it is reliable.