noble metals
貴金屬
No·ble a. [Compar. Nobler superl. Noblest ]
1. Possessing eminence, elevation, dignity, etc.; above whatever is low, mean, degrading, or dishonorable; magnanimous; as, a noble nature or action; a noble heart.
Statues, with winding ivy crowned, belong
To nobler poets for a nobler song. --Dryden.
2. Grand; stately; magnificent; splendid; as, a noble edifice.
3. Of exalted rank; of or pertaining to the nobility; distinguished from the masses by birth, station, or title; highborn; as, noble blood; a noble personage.
Note: ☞ Noble is used in the formation of self-explaining compounds; as, noble-born, noble-hearted, noble-minded.
Noble gas Chem., a gaseous element belonging to group VIII of the periodic table of elements, not combining with other elements under normal reaction conditions; specifically, helium, neon, argon, krypton, xenon, or radon; also called inert gas.
Noble metals Chem., silver, gold, and platinum; -- so called from their resistance to oxidation by air and to dissolution by acids. Copper, mercury, aluminium, palladium, rhodium, iridium, and osmium are sometimes included.
Syn: -- Honorable; worthy; dignified; elevated; exalted; superior; sublime; great; eminent; illustrious; renowned; stately; splendid; magnificent; grand; magnanimous; generous; liberal; free.