A small mark that sits on top of a letter and looks like a pointed hat: ^ . You see it most in French — hôpital, forêt, île, côte. It often shows that an older letter (very often s) used to be in the word, or that the vowel is said in a particular way. English almost never puts a circumflex on its own everyday words; when you see one in English, it is usually a borrowed French spelling that someone kept. People also call it a circumflex accent. There is an adjective use too — a circumflex accent, a circumflex vowel — but it is the same hat, not a new meaning. It is not the same mark as the little line going up (é, acute) or down (è, grave), and it is not the flat bar that means “long vowel” (the macron).

揚抑符（那個像帽子的 ^；別當成「長音符號」）