Ich habe keinen Hund.
English: I do not have a dog.
In German, 'kein' is used to make negative sentences with nouns. It means 'no' or 'not any' and replaces the article.
Use 'kein' to say that something does not exist or is not present. It is used with nouns that have no article or with indefinite nouns.
Ich habe keinen Hund.
English: I do not have a dog.
Wir trinken keinen Kaffee.
English: We do not drink coffee.
Sie hat keine Geschwister.
English: She has no siblings.
Es gibt kein Problem.
English: There is no problem.
Du kaufst keine Bücher.
English: You do not buy books.