A nanosecond is one billionth of a second (0.000000001 seconds). It is used to measure extremely short time intervals, especially in electronics and computing.
From *nano-* “one billionth,” based on Greek *nanos* “dwarf,” plus *second*, the basic unit of time. The prefix *nano-* became standard in the 20th century for very small scales in science and technology.
Light travels about 30 centimeters (roughly a foot) in one nanosecond, which means even tiny delays matter in high-speed electronics. When people say “I’ll be there in a nanosecond,” they’re jokingly promising something literally impossible. The word shrank “a moment” down to a scale our brains can barely imagine.
Complete word intelligence in one call. Free tier — 50 lookups/day.