The smallest MEASURABLE time unit known today, 1x10^(-24) seconds. Obviously, smaller units of time exist, but proper equipment and methodology for measuring them does not yet exist. Light travels 2.9979x10^(-16) meters in one yoctosecond, not the 3.33km stated above.
Learn to multiply. This isn't even an 'urban' word, so why is it defined here?
The smallest unit of time known today. It is on septillionth of a second, or about 0,000000000000000000000001 second(10^-24).
Light can travel a distance of approximately 3.33 kilometers in one yoctosecond.