An impenetrable headword, otherwise unattested in this form (apparently a neuter nominative plural, if the accent is correct). Manuscript A, which places this entry before tau 401, reads tetranai/a, but a later hand corrected n to r. Bernhardy suggested tetraori/a, "four-horse chariot" (in Pindar and elsewhere).
In Theodore Prodromus, Carmina Historica, 51 (title), tetrarai/as (genitive singular) seems to be a mistake for tetartai/as "quartan fever." In Constantine Porphyrogenitus, De Cerimoniis, tetrarai/wn appears to refer to some kind of military equipment. E.A. Sophocles' Lexicon has an entry tetrare/a "apparently a mistake for petrare/a = petrari/a"; and this last means a stone-throwing catapult.