Before the modern system of "formal", "semi-formal", and "informal" was consolidated in the 20th century, the terms were looser. In the 19th century, during the Victorian and Edwardian periods, the principal classifications of clothing were "full dress" and "undress", and, less commonly the intermediate "half dress". "Full dress" covered the most formal option: frock coat for day wear, and dress coat (white tie) for evening wear (sometimes with supplementary alternative being a full dress uniform independent of what time of the day). As such, "full dress" may still appear in use designating formal wear.