Possessive adjectives show who owns something. They come before the noun in German and agree with the noun like articles. The owner determines the possessive adjective, the object possessed determines the grammatical gender, number, and case of the form. In a sentence, the possessive adjective indicates: This thing belongs to this person.

The base forms are mein, dein, sein, ihr, unser, euer, Ihr and ihr. The stem stays the same for a possessor and is completed for the noun with endings. 'Ihr' with a capital I stands for politeness and is treated like a name. The plural 'ihr' stands for several owners in the plural and is not the same as 'ihr' for them in the singular.

The possessive adjective stands directly before the noun it refers to. It can be combined with adjectives and then remains before the noun. Definite articles and possessive adjectives are usually not used together before the same noun. The possessive adjective forms a unit with the noun in the sentence.

The ending of the possessive adjective depends on the case: nominative, accusative, dative or genitive. The case is determined by its function in the sentence, not by the possessive itself. The subject often needs the nominative and the direct object the accusative. Prepositions often require the dative or accusative and thus govern the form on the noun.

The grammatical gender of the noun determines the typical ending in the nominative singular. Masculine and neuter often have no ending: my dog, my book. Feminine usually has the ending -e in the nominative singular: my cat. In the plural, the nominative is usually also -e: my books.

In the nominative, masculine and neuter usually have the form without an ending, feminine and plural usually have -e. The nominative is used when the possessed object is the subject or after "to be" as a predicate. In "mein Vater ist Arzt" the "mein Vater" is in the nominative.

In the accusative, masculine typically takes the ending -en: meinen. Feminine and plural usually stay with -e, neuter usually remains mein. The accusative is often used for the direct object, for example after "haben" or "sehen".

In the dative singular, masculine and neuter usually end in -em: meinem. In feminine, the dative singular usually ends in -er: meiner. In the plural, the dative is usually -en and often also ends with -n on the noun, if possible: meinen Büchern.

In the genitive singular, masculine and neuter usually have -es or -en on the possessive or noun: meines. In feminine and plural, the genitive often has -er on the possessive: meiner. The genitive expresses belonging, but in everyday usage it is often replaced by 'von' phrases.

'Ihr' with a capital I is used for formal address and is treated like a name: 'Ihr Buch', 'Ihre Tasche'. The endings still depend on the noun's gender, number, and case. In letters and in conversations with 'Sie', 'Ihr' is capitalized and refers politely to the person being addressed.

The main endings for 'mein' at a glance: Nominative masculine and neuter: mein; feminine and Plural meine. Accusative: masculine meinen, feminine meine, neuter mein, Plural meine. Dative: masculine and neuter meinem, feminine meiner, Plural meinen. Genitive: masculine and neuter meines, feminine and Plural meiner.