Grammatical case

Grammatical case is a system in which changes to nouns or related words mark their roles in a sentence, such as subject, object, or possessor.

Nominative case: A case commonly used to mark the subject of a clause. It often marks the noun phrase performing the central role in a clause.
Grammatical relation: A syntactic relationship, such as subject or object, between a phrase and a clause. Case often signals these relationships, though the two are not identical.
Ergative–absolutive alignment: A pattern that groups intransitive subjects with transitive objects and distinguishes transitive subjects. It shows that case systems can organize sentence roles differently from nominative–accusative systems.
Word order: The arrangement of words or phrases in a sentence. Languages may rely more on position when case marking is limited.
Accusative case: A case commonly used to mark the direct object of a verb. It distinguishes many objects from subjects through noun-phrase marking.
Subject (grammar): A clause constituent commonly associated with the predicate and often controlling agreement. The subject is a frequent role marked by nominative case.
Nominative–accusative alignment: A pattern that groups intransitive and transitive subjects, distinguishing them from transitive objects. It is a common alignment pattern in which nominative and accusative cases often participate.
Analytic language: A language that relies relatively little on inflection and often uses separate words to express grammatical relationships. Analytic structures can express relations without extensive case inflection.
Genitive case: A case commonly marking possession, origin, or other relationships between nouns. It shows how case marks relations within noun phrases, not only clause roles.
Object (grammar): A clause constituent that is commonly selected by a verb or preposition. Objects are often distinguished from subjects by case marking.

Linked from 18 pages