When the weather beaver on the local television news talks about fog, he/she really isn’t.
Fog is an atmospheric aerosol formed of water particles, usually with a dust nucleus, for which the visibility – can you see a black telephone pole against a cloud background – is one kilometer (0.6 Imperial or American miles.)
An atmospheric aerosol formed of water particles for which the visibility is greater than one kilometer is a Haze.
You can also tell a fog by the size of the three-dimensional halo around a street lamp although this only helps if it is dark so that (a) the street lamp is lit and (b) you can see the halo.
An ice fog is an atmospheric aerosol formed of water particles that have frozen so that technically they are ice particles.
For some reason, weather beavers (TV meteorologists) like to call all atmospheric aerosols fog, possibly (?) because they think the technical distinctions are too complicated for their viewers.