a diacritical mark (^) placed above a vowel in some languages to indicate a special phonetic quality
中英词源
circumflex 音调符号
circum-,圈,周围,-flex,弯,转,见flexible.因形如小圆圈而得名。
circumflex (n.)
1570s, from Latin (accentus) circumflexus, "bent around," past participle of circumflectere "to bend around," of a charioteer, "turn around" (from circum "around;" see circum-, + flectere "to bend;" see flexible); used as a loan-translation of Greek (prosodia) perispomenos (Dionysius of Halicarnassus), literally "drawn-around," with reference to shape.