Please Note: These are only common assumptions and suggestions about writing an abstract. The requirements of such assignments often vary, so please follow your instructor's guidelines.
An abstract is a summary of a longer work. Typically, while researching in databases, you will see abstracts with journal articles to help you decide if the articles are useful without having to read all of them first.
The most common situation in which you might write an abstract is for an essay in APA style, which generally does not ask for more than 250 words. However, your professor's guidelines should always be followed. Being a summary, the abstract will need to capture your essay's thesis and as many of its main points as possible.
For some helpful information on writing summaries and abstracts, please see the following links: