"Magic #7" refers to a psychological concept suggesting that the average number of items an individual can hold in their working memory is about seven. This idea was popularized by psychologist George A. Miller in his 1956 paper, where he noted that people can typically remember seven plus or minus two pieces of information at a time. This principle has implications in various fields, including education, marketing, and user interface design. For example, when creating phone numbers or lists, breaking information into groups of seven or fewer can enhance recall and understanding, making it easier for people to process and remember the information presented.