- flossA thread used to clean the gaps between the teeth.
- flocA floccule; a soft or fluffy particle suspended in a liquid, or the fluffy mass of suspended particles so formed.
- flocculentFlocculated, resembling bits of wool; woolly.
- floccusA cloud species which consists of rounded tufts of cloud, often formed by dissipation from larger cloud species. Associated with cirrus, cirrocumulus, altocumulus, and stratocumulus genera.