This is the standard SI unit for time. In day-to-day language, it is how long it takes for a clock to tick once, approximately the amount of time it takes to fully blink, or about how long it takes to say 'one thousand' at a moderate pace.

A second is defined as the duration of \(9, 192, 631, 770\) periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of a cesium-133 atom.