standard form
noun [ U ] mathematics specialized uk/ˈstæn.dəd ˌfɔːm/ us/ˈstæn.dɚd ˌfɔːrm/ (also standard index form)
（书写非常大的数字时的）标准形式
a way of writing a very large number with one number before the decimal point, multiplied by a power of 10. For example, 280,000 is 2.8 × 105