Genitive case

The genitive case is an adjectival form of a noun that shows some sort of relationship between itself and what it describes. In a general sense, this genitive relationship may be thought of as one thing belonging to, being created from, or otherwise deriving from some other thing.

Specific varieties of genitive relationships include:

origin ("men of Rome")
composition ("wheel of cheese")
part of a mass ("a pound of beef")
number of distinct items (Old English "féower manna"; literally, "four of men")
relationship ("Janet's husband")
subjectivity ("my leaving")
objectivity ("the archduke's murder")
description ("man of honor", "day of reckoning")
inalienable possession ("my height", "his existence", "her long fingers")
alienable possession ("his jacket", "my drink")

The last two relationships are the most commonly expressed by the genitive.

Several languages have genitive cases, including Latin, Greek, German, Russian, Finnish and Sanskrit.

It is a common misconception that English nouns have a genitive case, marked by the possessive -'s ending. Linguists generally believe that English possessive is no longer a case at all, but has become a clitic, an independent particle which, however, is always written and pronounced as part of the preceding word. This can be shown by the following example: 'The King of Sparta's wife was called Helen.'. If the English -'s were a genitive, then the wife would belong to Sparta; but the -'s attaches not to the word 'Sparta', but to the entire phrase 'King of Sparta'.

That is not to say that the English possessive did not have its origins as a genitive case; but it has developed into being a clitic instead. In Old English, a common singular genitive ending was -es. The 18th century explanation that the apostrophe might replace a genitive pronoun, as in "the king's horse" being a shortened form of 'the king, his horse', is erroneous. Rather, the apostrophe is replacing the 'e' from the Old English morphology.

A few remnants of the genitive case do remain in Modern English in a few pronouns as whose, the genitive form of who; likewise, my/mine, his/hers/its, our/ours, their/theirs. See also Declension in English.

In astronomy, it is important to know the genitive form of the Latin names of constellations, because these are used along with letters of the Greek alphabet to name stars. For example, since the genitive of Gemini is Geminorum, the star Castor, brightest in the constellation Gemini, is named α Geminorum. For more details, see Bayer designation.