Term: fluorine: a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite
Broader: chemical element: any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter | Unrelated: foxtail millet: coarse drought-resistant annual grass grown for grain, hay, and forage in Europe and Asia and chiefly for forage and hay in United States