Grammatical Case
Case is a special grammatical category of a noun, pronoun, adjective, participle or numeral whose value reflects the grammatical function performed by that word in a phrase, clause or sentence. In some languages, nouns, pronouns, adjectives, determiners, participles, prepositions, numerals, articles and their modifiers take different inflected forms, depending on their case.
English has largely lost its case system although personal pronouns still have three cases, which are simplified forms of the nominative, accusative and genitive cases. They are used with personal pronouns: subjective case (I, you, he, she, it, we, they, who, whoever), objective case (me, you, him, her, it, us, them, whom, whomever) and possessive case (my, mine; your, yours; his; her, hers; its; our, ours; their, theirs; whose; whosever ). Forms such as I, he and we are used for the subject ("I kicked the ball"), and forms such as me, him and us are used for the object ("John kicked me").