FLUORINE n.
ongly acid or negative, or associated with chlorine, bromine, and iodine, in the halogen group of which it is the first member. It always occurs combined, is very active chemically, and possesses such an avidity for most elements, and silicon especially, that it can neither be prepared nor kept in glass vessels. If set…
FOIL n.
cusps in Gothic architecture; a rounded or leaflike ornament, in windows, niches, etc. A group of foils is called trefoil, quatrefoil, quinquefoil, etc., according to the number of arcs of which it is composed. Foil stone, an imitation of a jewel or precious stone.
FUNGUS n.
Any one of the Fungi, a large and very complex group of thallophytes of low organization, -- the molds, mildews, rusts, smuts, mushrooms, toadstools, puff balls, and the allies of each.