the twenty-first letter of the Greek alphabet (Φ, φ), transliterated as ‘ph’ or (in modern Greek) ‘f’ 希腊字母表中第二十一个字母(译写为ph,现代希腊语中译写为f) ■(Phi)[followed by Latin genitive](Astronomy)the twenty-first star in a constellation (天文)φ星(星座中第二十一颗星) Phi Eridani. 波江座φ星。
symbol for
■(φ)a plane angle 平面角 ■(φ)a polar coordinate. Often coupled with θ 极坐标(常与θ成对使用)