An article must agree with the noun it modifies in case, number, and gender. Below is the complete declension of the definite article. Notice that the endings are very similar to noun endings.
| Masculine | Feminine | Neuter |
Singular | | | |
Nominative | ὁ | ἡ | τό |
Genitive | τοῦ | τῆς | τοῦ |
Dative | τῷ | τῇ | τῷ |
Accusative | τόν | τήν | τό |
Plural | | | |
Nominative | οἱ | αἱ | τά |
Genitive | τῶν | τῶν | τῶν |
Dative | τοῖς | ταῖς | τοῖς |
Accusative | τούς | τάς | τά |