What is "joule-second"

The joule-second (J s or J·s) is a unit equal to a joule multiplied by a second, used to measure action. The action of a system has the dimensions of energy integrated over time; it is therefore measured in joule-seconds. The joule-second is the unit used for Planck's constant.

In SI base units, the joule-second is $\frac{kg \cdot m^{2}}{s}=J \cdot s.$