Lameen Souag, in his Jabal al-Lughat post No, Berber isn’t descended from Arabic, rebuts some “unscientific jingoistic claptrap” that claims what the title denies. But the comment thread turns into a discussion of one of his examples, a Berber word that is borrowed from Arabic: “abrid ‘road’ < Ar. barīd بريد (confirmed by the Tuareg pronunciation of this word, abărid)." Lameen explains that "barīd (primary meaning in modern standard Arabic: post) comes from Greek beredos 'post-horse', which is from Latin veredus 'post-horse'," but then it turns out that "barīd might be a borrowing into Arabic from Persian, rather than Greek - in which case the word for this key tool of government has been passed on from one empire to the next ever since the Akkadians." It's well worth a read by anyone interested in these things.