Anitra L. Freeman
I describe an essay as "an attempt at words." It is both the easiest and the most structured writing form. Any letter, email, memo or college paper can be called an essay. Usually the term is kept for non-fiction writing that is more subjective than a news article an expression of opinion or emotion.
For the first two years that I wrote for Real Change street newspaper, I would turn in what I thought were articles and Tim Harris Editor God would inform me that they were editorials. It is not better or worse to write editorials or news articles but it is best to know which is which, whether you are reading or writing.
An article may not be tied to a specific event; a news article must be. Any kind of article may convey the emotions and opinions of its author it is almost impossible not to do so, and personally I don't think such writing would be worth reading. But articles generally focus on facts and tend to present more sides of an issue than an editorial does. Articles are generally intended to inform, not to persuade editorials usually intend to do both.
Lately a new genre has developed called "creative journalism." It is an attempt to inject more individual personality into news stories while keeping the standards of honest reporting. It gets mixed reviews.
Speaking of reviews: a book or movie review, or even a music review, can go either way tending to more of an essay, or more of an article.
Then there is the interview. To ask the right questions and to pick out of hours of answer the quotes that most accurately represent the person being interviewed is also a writerly challenge.
I've collected a full range of my non-fiction entries here. You can decide
for yourself how much is opinion and how much is fact. :)