In certain political circles, they insist on spelling this "nader", as in Ralph, with the same definition!

That's precisely what I thought when I saw today's word! Great (or is it grate) minds in the same gutter? While politically allied with Ralph, I think of Jim Hightower and Molly Ivins in Zenith terms!

What surprised me is that nadir had a French connection, and did not come directly into English through Arabic. I understand the Spanish connections of Arabic words, but how French?