noun
A unit of time equal to one billionth of a second. Used in scientific, computing, and technical contexts.
このプロセッサのクロック周期は数ナノ秒です。
The clock cycle of this processor is a few nanoseconds.
光は1ナノ秒に約30センチメートル進む。
Light travels about 30 centimeters in one nanosecond.