# Are measurements of time and distance independent or always coupled by the speed of light

In texts about special relativity the light clock is usually described as a tool to measure time $t$. It counts how often light travels along a given distance $d$, i.e. $t = d/c$, where $c$ is the speed of light.

In other contexts, distance is defined by how far light travels in a given time $t_d$, i.e. $d = c\cdot t_d$.

Now I wonder if we have a way to define distance and time such that that not each one relies on the other one?

Is an atomic clock sufficiently different from a light clock so that we can say we do not base time measurement on distance measurement?