abjad
/ˈabdʒɑːd/(also abjud, abujad, abadjad)
noun
1A system of notation in which each of the 28 letters of the Arabic alphabet is assigned a numerical value. Now chiefly historical.
2 Linguistics. Any of various writing systems having symbols for consonants only; a consonantal alphabet.
Origin
Late 18th century. From Arabic abjad Arabic alphabet, system of notation in which each of the 28 letters of the Arabic alphabet is assigned a numerical value, acronym from the initial letters of alif, bā', jīm, dāl, the names of the first four letters of the Arabic alphabet in its historical order.