Both headword and gloss are neuter nominative/accusative singular, as in (e.g.) Etymologicum Gudianum and Etymologicum Magnum, but here without the definite article to/. Identical entry also in Timaeus Sophista, Platonic Lexicon s.v., probably from a scholion to [Plato], Axiochus 367B, which could be the original source. Note, nevertheless, the same neuter form and gloss twice in Nicander, with corresponding scholia: Theriaca 187, Alexipharmaca 157.
An alternative lexicographical tradition (Hesychius delta2513, Photius delta792 Theodoridis) is couched in the masculine nominative singular.
The adjective is rare before the Christian era but becomes much more frequent thereafter; first in medical literature (Philumenus Medicus, Galen, Aretaeus, Cassius Iatrosophus) and later, in the Byzantine era, in theology, philosophy, and philology.