Citing a source means that you show, within the body of your text, that you took words, ideas, figures, images, etc. from another place. Citations are a short way to uniquely identify a published work (e.g. book, article, chapter, web site) and consist of standard elements, such as author name(s), title of the work, date of publication, etc. Citations may look different, depending on what is being cited and which style was used to create them. Ask your professor which style is preferred for your course.