the ordinal number of one quadrillion in counting order
双语例句
1
The difference is approximately 2 quadrillionths (sixteen decimal places), and is therefore too small to be shown.
差异大约是两千万亿分之一（十六位小数），太小而无法显示。
2
Physicists have no trouble using, on the one hand, picoseconds (trillionths of a second) or even femtoseconds (quadrillionths of a second) to discuss time at the atomic scale.