Most German statements contain at least one conjugated verb and a subject. The subject performs the action expressed by the verb. The subject is active in the sentence or is central to the interest. A subject is generally a noun, a group of nouns or a personal pronoun.
When the subject is a noun with an article, the article takes one of the following forms:
This form is called the nominative.
The subject answers the question "Wer?" or "Was?" (wer for people and was for non-persons, for example animals or objects) and determines the form of the conjugated verb.
Grammatical terms in German:
das Subjekt: The subject is the person or thing that is active in the sentence or is central to the interest. It is generally a noun or pronoun.
A noun can have different functions in a sentence. For example, it can be a subject or an object. Depending on what function the noun has, its form can change. However, this change can best be seen in the form of the article. In German there are four different forms or categories (cases), known as Fälle or Kasus.
One of these cases is the nominative.
der Nominativ: The subject is always in the nominative. The articles are: der/ein, die/eine, das/ein, die/-.