Variant spelling of Endekalogue - which is better, as the number endeka is Greek for 11, and c is not used in Greek transcription (RS)
KBK is of two minds about RS's comment, since the correct spelling of the English word, Decalogue, is as it appears here. It came to English by way of mediaeval Latin, and so is removed one step further from the Greek deka-logos. By the same means, English has catalogue, and even endecane.
RS agrees, and thinks the story is even more complicated, since the trailing -ue seems to indicate that the word Decalogue came to English via French... So I withdraw my comment above.