The Arabs, I have said, took the flag or water leaf form and departed very far from the Egyptian original (we know from Plutarch that the hieroglyphic abecedarium began with "a"), which was chosen by other imitators, namely the bull's head, and which in the cursive form, especially the— Arabian nights. English
It relies for the first letter upon the authority of Plutarch, who asserts that the Egyptian abecedarium numbered the square of five— The Land of Midian — Volume 1
Abecedarium has been looked up 66 times, favorited once, listed 10 times, commented on twice, and is not a valid Scrabble word.