外交照会指外交部对外国使节，或各省长官对外交领事所递交的一种外交文书。亦即一国政府将彼此相关的某一事件的意见通知另一国政府。亦称「通牒」、「照会」。「照会」，意指「察照知会」。

A démarche (/deɪˈmɑːrʃ/; from the French word whose literal meaning is "gait") has come to refer either to

Diplomatic démarches are delivered to the appropriate official of the government or organization. Démarches generally seek to persuade, inform, or gather information from a foreign government. Governments may also use a démarche to protest or object to actions by a foreign government. Informally, the word is sometimes used as a verb to describe making or receiving such correspondence.