official and traditional special clothes and decorations, especially those worn or carried in formal ceremonies

The queen's regalia at her coronation included her crown and sceptre. 女王在加冕礼上的服饰包括王冠和权杖。

any set of special clothes

The biker was dressed in full regalia, with shiny black leather and lots of chains. 那个骑摩托车的人全副武装，皮衣乌黑发亮，链子挂满全身。