In Millennium: A History of the Last Thousand Years, chapter 4 ("The World Behind the Wind"), the second-to-last sentence:
On the evidence of the events of the fifteenth century, in the world east of the Bay of Bengal—the world "behind the wind", as Arab navigators called it—China could have [...]
There's more to the sentence, but it's not relevant to this question. (it's about why China didn't end up conquering Europe)
The part I'm interested in is the "the world 'behind the wind', as Arab navigators called it". Where was this term first used? i.e. he quotes Arab navigators, but which one and when?