| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
fluoridation fluor·i·da·tion (fl&oobreve;r'ĭ-dā'shən, flôr'-)
n.
The addition of a fluorine compound to drinking water for the purpose of reducing tooth decay.