from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A pale-yellow, highly corrosive, poisonous, gaseous halogen element, the most electronegative and most reactive of all the elements, used in a wide variety of industrially important compounds. Atomic number 9; atomic weight 18.9984; freezing point -219.62°C; melting point -223°C; boiling point -188.14°C; specific gravity of liquid 1.108 (at boiling point); valence 1. See Table at element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The chemical element (symbol F) with an atomic number of 9.
- n. A fluorine atom.
from the GNU version of the Collaborative International Dictionary of English
- n. A non-metallic, gaseous element of atomic number 9, strongly acid or negative, and 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, but may be contained in lead vessels. If set free it immediately attacks a containing glass vessel, so that it was not isolated until 1886. It is a pungent, corrosive, colorless gas. Symbol F. Atomic weight 19.00.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. 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
From Latin fluor ("flow") + -ine (Wiktionary)