Questions of Greek Grammar

...meaning it ends in ν with the vowel of the nominative.

Menelaus, menelai, menelao, menelaum, O menelae. Dual: menelai, menelaorum, and menelais, O menelai. Plural: menelai, menelaorum, menelais, menelaos, O menelai.

Area, areae, areae, aream, O area. Dual: areae, arearum, and areis, O areae. Plural: areae, arearum, areis, areas, O areae.

Ferax original: "Ferax" — likely used here as a placeholder for an adjective or Greek noun, feracis, feraci, ferax, O ferax. Dual: feracia, feracium, and feracibus, O feracia. Plural: feracia, feracium, feracibus, feracia, O feracia.

Fourth declension

The fourth declension of the noun is also in the three genders, and is isosyllabic, meaning all masculine and feminine nouns ending in os via the small o, and neuter nouns ending in on, except for comparatives, of which the genitive ends in ou, the dative in w, and the accusative ends in n with the vowel of the nominative.

Sermo, sermonis, sermoni, sermonem, O sermo, and O sermo. Dual: sermones, sermonum, and sermonibus, O sermones. Plural: ones, onum, onibus, ones, O sermones.

Via, viae, viae, viam, O via, and O via. Dual: viae, viarum, and viis, O viae. Plural: viae, viarum, viis, vias, O viae.

Lignum, ligni, ligno, lignum, O lignum. Dual: ligna, lignorum, and lignis, O ligna. Plural: ligna, lignorum, lignis, ligna, O ligna.

Fifth declension.