The national name Prussia (in Prussian: Prusa, German: Preußen, Polish: Prusy, Lithuanian Prūsai, Latin: Prussia or Borussia) was used by a wide variety of political factions during the 2nd millennium. At different times it has denoted a geographical region, a dukedom, a Polish province, a Polish fief, a kingdom under Brandenburg's rule which became the leading kingdom of the German Empire (comprising in its last form almost two-thirds of the Germany's area) and as republic state of Germany.

The word Prussia can refer to:

• the land of the Prussian people (6th-13th centuries)
• Teutonic Knights' or Teutonic Order state 13th-15th century
• Royal Prussia and Ducal Prussia forming together the Prussian province of Poland, 15th century-1660
• Kingdom of Prussia, 1701-1918
• The German state Prussia , 1871-1933
• West Prussia (since 1772) and East Prussia (since 1618), provinces of the Prussian State or Kingdom of Prussia, 1701-1933

• see also Prussian Confederation