Strong’s Greek
G4418 — pterna
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
πτέρνα
pterna — pronounced pter'-nah
of uncertain derivation; the heel (figuratively):--heel.
1 occurrence in the KJV.
John 13:18
I speak not of you all: I know whom I have chosen: but that the scripture may be fulfilled, He that eateth bread with me hath lifted up his heel against me.