The nominative case is used to indicate the subject of a sentence. It is also used for other nouns in the sentence which give more information about the subject. As it is the dictionary form for nouns and adjectives, you should memorize nouns and adjectives in their nominative case forms.
| Я иду́ в теа́тр. | I am going to the theater. |
| Кни́га на столе́. | The book is on the table. |
| Вот дом. | There is the house. |
| Э́то моя́ ру́чка. | This is my pen. |
| Мой брат - инжене́р. | My brother is an engineer. |
| В институ́те рабо́тают америка́нские фи́зики. | American physicists work in the institute. |
Because Russian has cases, word order in a sentence is less important than it is in English. The subject [that noun plus its modifiers in the nominative case] can come at the beginning, in the middle or at the end of the sentence. Knowing the nominative case endings for nouns and adjectives will help you find the subject of the sentence more quickly.
Adjectives are linked to their nouns by their endings. The adjective may stand in front of, after, or at a distance from the noun it modifies. You can always find the adjective which modifies a noun by looking for the one whose ending matches in gender, number, and case that of the noun.
Э́то Бе́лый дом.
Она́ учи́тельница хоро́шая, о́пытная.
Ру́сский язы́к о́чень интере́сный, но тру́дный.