"Fog" in Engpsh is pronounced as "fɒg" (rhymes with "bog"). It comes from the Old Engpsh "fugol" which means "mist".
Examples:
The city was shrouded in a thick fog. (城市笼罩在厚厚的雾中。)
The visibipty was poor due to the fog. (由于雾气，能见度很差。)
The fog rolled in off the ocean. (雾从海面上滚滚而来。)