In grammar, genitive (abbreviated ; also called the possessive case or second case) is the grammatical case that marks a noun as modifying another noun. It often marks a noun as being the possessor of another noun. However, it can also indicate various relationships other than possession: certain verbs may take arguments in the genitive case, and it may have adverbial uses ("see" Adverbial genitive). 

Placing the modifying noun in the genitive case is one way to indicate that two nouns are related in a genitive construction. Modern English typically does not morphologically mark nouns for a genitive case in order to indicate a genitive construction; instead, it uses either the "" clitic or a preposition (usually "of"). However, the personal pronouns do have distinct possessive forms. There are various other ways to indicate a genitive construction, as well. For example, many Afroasiatic languages place the head noun (rather than the modifying noun) in the construct state. 

Many languages have a genitive case, including Albanian, Arabic, Armenian, Basque, Dutch, Estonian, Finnish, Georgian, German, Greek, Icelandic, Irish, Latin, Latvian, Lithuanian, Romanian, Sanskrit, Scottish Gaelic, Tamil, Telugu, Turkish and all Slavic languages except Bulgarian and Macedonian. English does not have a proper genitive case, but a possessive ending, "’s", although some pronouns have irregular possessive forms which may more commonly be described as genitives; see English possessive.
Does more than one language have a genitive case?
How many?
Does English?
How about Bulgarian?
What does English use to indicate a genitive construction?
Does this case mark a noun as modifying another noun?
Can it indicate many different relationships other than possession?
Is this case capable of of indicating two nouns are related?
What languages place the head noun in the construct state?
Can a genitive case possibly have adverbial uses?
yes
Many languages have a genitive case
Many languages
Many languages
not properly
English does not have a proper genitive case
no
all Slavic languages except Bulgarian and Macedonian
the "" clitic or a preposition
instead, it uses either the "" clitic or a preposition
no
English typically does not morphologically mark nouns for a genitive case
yes
indicate various relationships other than possession
yes
It often marks a noun as being the possessor of another noun
Afroasiatic
many Afroasiatic languages place the head noun (rather than the modifying noun) in the construct state
yes
in the genitive case, and it may have adverbial uses