"one of the native people of Arabia and surrounding regions," late 14c. (Arabes, a plural form), from Old French Arabi, from Latin Arabs (accusative Arabem), from Greek Araps (genitive Arabos), from Arabic 'arab, indigenous name of the people, perhaps literally "inhabitant of the desert" and related to Hebrew arabha "desert."
The meaning "homeless little wanderer, child of the street" is from 1848 (Arab of the city, but the usual form was city arab), an allusion to the nomadic ways of the Bedouin. The Arab League was formed in Cairo, March 22, 1945.
"alliance," mid-15c., ligg, from French ligue "confederacy, league" (15c.), from Italian lega, from legare "to tie, to bind," from Latin ligare "to bind" (from PIE root *leig- "to tie, bind"). Originally among nations, subsequently extended to political associations (1846) and sports associations (1879). League of Nations is attested from 1917 (created 1919).