natural number
noun [ C ] mathematics specialized uk/ˌnætʃ.ər.əl ˈnʌm.bər/ us/ˌnætʃ.ɚ.əl ˈnʌm.bɚ/
自然数
a whole number (= a number such as 1, 3, or 17, that has no fractions and no digits after the decimal point) that is greater than zero, or sometimes that includes zero itself