An international philosophy and style of art, architecture and other decorative arts that were most popular during 1890–1910.

A reaction to academic art of the 19th century, it was inspired by natural forms and structures, not only in flowers and plants but also in curved lines. Architects tried to harmonise with the natural environment. It is also considered a philosophy of design of furniture, which was designed according to the whole building and made part of ordinary life.

Notable contributions include the architect Gaudi, Guimard's Paris metro entrances, Klimt, Mucha, Charles Rennie Mackintosh, Lalique, Tiffany and Gallé.

Although Art Nouveau was replaced by 20th-century modernist styles, it is now considered as an important transition stage from the earlier Neoclassicism.