Art Nouveau is an international style of art, architecture and applied art, especially the decorative arts, known in different languages by different names: Jugendstil in German, Stile Liberty in Italian, Modernisme in Catalan, etc. In English it is also known as the Modern Style (not to be confused with Modernism and Modern architecture).

The style was most popular between 1890 and 1910. It was a reaction to the academic art, eclecticism and historicism of 19th century architecture and decoration and was inspired by natural forms and structures, particularly the curved lines of plants and flowers, and whiplash forms. Other defining characteristics of Art Nouveau were a sense of dynamism and movement, often given by asymmetry and by curving lines, and the use of modern materials, such as iron pillars and railings, sculpted and curved in naturalistic designs.

One major objective of Art Nouveau was to break down the traditional distinction between fine arts (especially painting and sculpture) and applied arts. It was most widely used in interior design, graphic arts, furniture, glass art, textiles, ceramics, jewelry and metal work. The style responded to leading nineteenth-century theoreticians, such as French architect Eugène-Emmanuel Viollet-le-Duc (1814–1879) and British art critic John Ruskin (1819–1900).

More Info: en.wikipedia.org