Usually when you hear the word "definition" you think of a dictionary or encyclopedia. For example, a juvenile delinquent is an underage person convicted of crime or antisocial behavior. Likewise, a venture capitalist is a person who provides money for innovative projects.
Perhaps you have written a narrative essay about a personal experience in which you are called upon to classify and to analyze causes and effects. All of these patterns and more can be used in your paragraphs to clarify and extend the term you have chosen.
Sometimes a single pattern will be sufficient to extend the definition to achieve the effect you want for your audience. For example, let's say in an introductory sociology course, you are introducing the term "juvenile delinquent" to the class. You could use the "classify" pattern to clarify how broadly the term in used in this field:
Depending on the term, you may find that using several patterns is the best way to help shape your audience's understanding of a term. For example, let's consider the innocent sounding term "arbitration." Maybe you wish to make the point that sometimes legal terms are used to desensitize us from what is really taking place. Consider this example:
Your task in writing an extended definition is to add to the standard/notional definition in a way that will allow your audience to gain a deeper and more nuanced understanding of the term in a particular context. Whether you do this by adding facts, telling what a term does not include, or applying any of the many development patterns (classify, illustrate, cause/effect, compare/contrast, narration, description), matters not. Only the development of clear understanding between you and your audience should be the ultimate goal.