The second (SI symbol: s), sometimes abbreviated sec., is the name of a unit of time, and is the International System of Units (SI) base unit of time. SI prefixes are frequently combined with the word second to denote subdivisions of the second, for example, the millisecond (one thousandth of a second) and nanosecond (one billionth of a second). Though SI prefixes may also be used to form multiples of the second (such as “kilosecond,” or one thousand seconds), such units are rarely… (More on Second)