奥古斯都（拉丁文 Augustus的中译，复数型 Augusti）的原意为「神圣的」、「高贵的」，带有宗教与神学式的意味。它的阴性型为奥古斯塔（Augusta）。

希腊文的同义字是「Σεβαστός」（Sebastos），或将拉丁语转写而成的「Augoustos」。一般奥古斯最常用来指称罗马帝国的第一公民——屋大维；但奥古斯都也同样可以用作为罗马皇帝的头衔。罗马帝国灭亡之后，欧洲许多贵族也常使用奥古斯都当男子名，特别是在神圣罗马帝国的境内。

Augustus (plural augusti), /ɔːˈɡʌstəs/; Classical Latin: [awˈɡʊstʊs], Latin for "majestic," "the increaser," or "venerable"), was an ancient Roman title given as both name and title to Gaius Octavius (often referred to simply as Augustus), Rome's first Emperor. On his death, it became an official title of his successor, and was so used by Roman emperors thereafter. The feminine form Augusta was used for Roman empresses and other females of the Imperial family. The masculine and feminine forms originated in the time of the Roman Republic, in connection with things considered divine or sacred in traditional Roman religion. Their use as titles for major and minor Roman deities of the Empire associated the Imperial system and Imperial family with traditional Roman virtues and the divine will, and may be considered a feature of the Roman Imperial cult.