Kalmar "Jack Frost" tana nufin yanayin yanayin hunturu ko sanyi, yawanci ana kwatanta shi azaman ɓarna da wasa wanda ke kawo sanyi, dusar ƙanƙara, da kankara zuwa wuri mai faɗi. Yawancin lokaci ana amfani da kalmar a cikin adabi da waƙa don kwatanta yanayin sanyi ko zuwan hunturu. Ana yawan amfani da sunan "Jack" a cikin tatsuniyoyi na Turanci don wakiltar jinsin maza, kuma "Frost" yana nufin yanayin sanyi.