They are mostly proper names and are declined as follows in the Singular, the Plural, when found, being regular: -
|o||mýthos, M.||Athós, M.||Délos, F.||Ílion, N.|
|o GEN.||mýthí||Athó (-í)||Délí||Ílií|
|o ACC.||mýthon||Athón (-um)||Délon (-um)||Ílion|
a. Many names in -és belonging to the third declension have also a genitive in -í: as, Thúcýdidés, Thúcýdidí (compare §44. b).
b. Several names in -er have also a nominative in -us: as, Teucer or Teucrus. The name Pauthús has the vocative Panthú (§81. 3).
c. The genitive plural of certian titles of books takes the Greek termination -ón: as, Geórgicón, of the Georgics.
d. The termination -oe (for Greek -oi) is sometimes found in the nominative plural: as, Adelphoe, the Adelphi (a play of Terence).
e. Greek names in -eus (like Orpheus) have forms of the second and third declensions (see §82).