Yes, a fog is simply a cloud that touches the ground. The only difference between fog and clouds is the altitude at which they form. Fog occurs when visible moisture forms at a height lower than 50 feet. If the moisture forms at or above 50 feet, it is called a cloud.
So, while fog and clouds are essentially the same phenomenon, fog is simply a special type of cloud that happens to be close enough to the ground to be considered fog.
