Art déco (short for French art décoratif, "decorative art") was a movement in the design history from about 1920 to 1940, which included the shaping of objects in many areas of life such as architecture, furniture, vehicles, dressmode, jewelery or utensils . Also paintings and illustrations were made in Art Deco style.
If you find Russian silver in pure (real) Art Deco style, marked between 1908 and 1917 - it is always a fake! There were some similar tendencies starting before 1920 (Vienna) and the artists of the Russian Artels experimented with new styles. Here an example from my collection, milk vessel, made by the 5th Artel. Note: this is no pure Art Deco! To prevent the usual negative comments - the last photo shows the bottom of the sugar vessel!