The phrase "perfect dress" can have different meanings depending on the context in which it is used. Generally, however, when someone says that they've found their perfect dress, what they are implying is that this particular piece of clothing meets all of their criteria and preferences for a dress. It could be because it fits them perfectly or because it has an attractive design or color scheme that appeals to them. In other words, the person feels that this dress is exactly what they were looking for in terms of style, fit, and overall appearance.