Greek nouns have case, or different forms which express their relationship to other things.  The closest analogy in English are the different forms of pronouns:  “I,” which is used as a subject, is like nominative case in Greek; “my,” indicating posession, is like genitive; and “me,” an object, is like dative or accusative.  For example:  in Greek, to express the idea “of the ocean,” the genitive of  ὁ ὠκεανός would be used:  τοῦ ὠκεανοῦ.

The Greek cases are:
– nominative, or the subject of a verb;
– genitive, indicating posession or origin (like the use of “of” in English);
– dative, the indirect object of a verb, or location (like “to” or “for” in English);
– accusative, the direct object of a verb; and
– vocative, direct address.

Here are the cases of the singular form of the word ἄνθρωπος, “man”:

nominative   ὁ ἄνθρωπος (the man)
genitive   τοῦ ἀνθρώπου (of the man)
dative   τῷ ἀνθρώπῳ (to or for the man)
accusative   τὸν ἄνθρωπον (the man—direct object)
vocative   ἄνθρωπε (direct address; no definite article)

ὁ βίος τοῦ ἀνθρώπου thus means “the life of the man.”

See if you can figure out the following phrases and sentences.  The translations are at the bottom of the page.

Word list:  ἀδελφός, “brother”;  λόγος, “word”;  φίλος, “friend”;  πέμπει, “sends”;  φέρει, “carries”;  Εὐκλείδης, “Euclid”;  Νεῖλος, “Nile”;  ταῦρος, “bull”;  φωνή, “sound”;  ὠκεανός, “ocean.”

1.  ὁ λόγος τοῦ φίλου

2.  ἡ φωνὴ τοῦ ὠκεανοῦ

3.  ὁ ἄνθρωπος φέρει τὸν ἀδελφόν.

4.  Εὐκλείδης πέμπει ταῦρον τῷ Νείλῳ.

Adjectives use the same case as the nouns they modify:  τῷ μικρῷ ἀνθρώπῳ, “to the small man.”

1.  the word of the friend
2.  the sound of the ocean
3.  The man carries the brother.
4.  Euclid sends a bull to the Nile.