The term combines the SI prefix nano- indicating a 1 billionth submultiple of an SI unit (e.g. nanogram, nanometre, etc.)
and second, the primary unit of time in the SI.
A nanosecond is equal to 1000 picoseconds or 1/1000 microsecond.
Time units ranging between 10−8 and 10−7 seconds are typically expressed as tens or hundreds of nanoseconds.
Time units of this granularity are commonly found in telecommunications, pulsed lasers, and related aspects of electronics.