Nouns describe people, animals, things, concepts and ideas. Just as in English, German nouns can be common or proper, count or mass, singular or plural. German nouns, however, have two additional characteristics: they are always capitalized and they can be masculine, feminine or neuter:
Common vs. proper nouns
Common nouns refer to a general person, animal, object or concept.
Proper nouns represent specific individuals or places.
Count vs. mass nouns
Nouns can also be categorized according to whether they can be counted or not. Nouns that can be broken down into individuals are count nouns.
Nouns that denote items that cannot be broken down into individual units are mass nouns.
German nouns also all have a grammatical gender that sometimes overlaps with the biological gender (masculine or feminine), as in the following examples:
But most often the grammatical gender is independent of biological gender, and the only thing to do with them is to learn them when you learn your vocabulary.
All nouns in German and English are marked for number: singular (one) or plural (more than one). Typically, in English there is some kind of ending that marks the plural, for example an -s: stone => stones; tree => trees. There can be other kinds of plural markers, such as a different word form as in child => children. In German the situation is the same, there is typically some kind of ending that indicates whether we are talking about one item or more:
Mass nouns only have one form and cannot be made into the plural. Here are some examples from Rotkäppchen's life: der Lärm (noise).
Similarly, nouns that refer to abstract concepts do not have a plural: