Genesis 19:38

The younger daughter also had a son, and she named him Ben-Ammi ; he is the father of the Ammonites of today.

(New International Version)

As for the younger, she also bore a son, and called his name Ben-ammi; he is the father of the sons of Ammon to this day.

(New American Standard Bible)

And the younger, she also bare a son, and called his name Benammi: the same is the father of the children of Ammon unto this day.

(King James Version)