An abecedarium (or abecedary)'s an inscription consisting of the letters of the alphabet, almost always listed in order. Typically, abecedaria (or abecedaries) are practice exercises. Some abecedaria include obsolete letters which aren't otherwise attested in inscriptions. For example, abecedaria in the Etruscan alphabet from Marsiliana (the Tuscana town) include the letters B, D, and O, which indicate sounds not present in the Etruscan language and are therefore not found in Etruscan inscriptio… (More on Abecedarium)