Definite article for singular neutral: das. For people, article 'das' is usually used for young people. E.g: baby (das Baby), child (das Kind), girl (das Mädchen)
Definite article for plural: die. Same article just like singular feminine. Plural: more than one person. E.g: parents (die Eltern), siblings (die Geschwister), chidren (die Kinder).
Extra fun fact: Do you know the word kindergarten in English originated from German words? Kinder (children) Garten (garden). Another word is Kinder Bueno. Kinder is a German word. Bueno is a Spanish word.
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