Abjad (ا‎, ب‎, ج‎, د‎), is the sequence of the first four letters of the twenty-two Semitic consonants, which are generally referred to as the early order of the Arabic alphabet.

The Arabic alphabet derives originally from Aramaic, through one of its main branches, the Nabataean language and script (see Azarnoosh, 75 et passim). However, as the classical North Semitic system contained no more than 22 consonants arranged in six groups, the remainder of the consonants used in Arabic, which comprises a total of 28 basic letters, were added later in the form of the two groups of thakhidh (ثخذ…