The father of a father is a grandfather, a grandfather's father is a great-grandfather, a great-grandfather's father is a great-great-grandfather, but no word has been decided upon for the generations before great-great-grandfather.
أبو الأب جد و أبو الجد الجد الأكبر و أبو الجد الأكبر جد الجد لكن لم يُحدد اسم لمن سبقهم من الأجداد.