The second is (and has been) defined independent of length for a while. It's the time it takes for a certain number oscillations of a caesium atom. The meter

The second is (and has been) defined independent of length for a while. It's the time it takes for a certain number oscillations of a caesium atom. The meter was redefined as the distance light travels in a specific time. So you could say that either the meter or the speed of light was redefined to make the speed of light a round constant, but not the second.