一切經音義 12.201

12.201

足跟（艮恩反字統云足後曰跟從足艮聲也）。

足跟 (heel of the foot): 跟 is *gēn* (艮恩反 [kən]); the *Zitong* says: "The back of the foot is called the heel (跟); it takes the foot radical with 艮 as its phonetic."