The new president solemnly recited the oath of allegiance during the inauguration ceremony.

oath 是名词，意思是"誓言、宣誓"，指一种正式的承诺或声明，通常具有法律或道德约束力。在正式场合如就职典礼上，oath 特指官员就职时作出的效忠宣誓。