Define and Describe
When starting a new 118Wiki article, it's important to set out to define and describe the subject.
- To define a concept means, essentially, to make its meaning unambiguous and adequately precise. To do this you must show not only what a concept is, but what it isn't. You must show how the concept relates to other concepts of the same class, thereby establishing the limits of the concept.
- The description differs from the definition in that it shows the properties of the concept, rather than how the concept relates to others of the same class. Description without definition is mere anecdote. 
If an article is longer than about one page, after you define and describe the subject, you should use the remainder of the opening paragraph to summarize it.
See also: Establishing context