Second

  1. When referring to time, a second or sec is a very brief moment of time that is equal to one sixtieth (1/60) of a minute.
  2. When referring to a number, second is after first; number two.
  3. When referring to a version or a release, second refers to the release after the initial release of a product.

Also see: Microsecond, Millisecond, Nanosecond