The Collaborative International Dictionary of English v.0.48:

Noble \No"ble\, a. [Compar. Nobler; superl. Noblest.] [F.
   noble, fr. L. nobilis that can be or is known, well known,
   famous, highborn, noble, fr. noscere to know. See know.]
   1. Possessing eminence, elevation, dignity, etc.; above
      whatever is low, mean, degrading, or dishonorable;
      magnanimous; as, a noble nature or action; a noble heart.
      [1913 Webster]

            Statues, with winding ivy crowned, belong
            To nobler poets for a nobler song.    --Dryden.
      [1913 Webster]

   2. Grand; stately; magnificent; splendid; as, a noble
      edifice.
      [1913 Webster]

   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.
      [1913 Webster]

   Note: Noble is used in the formation of self-explaining
         compounds; as, noble-born, noble-hearted, noble-minded.
         [1913 Webster]

   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.
      [1913 Webster]

   Syn: Honorable; worthy; dignified; elevated; exalted;
        superior; sublime; great; eminent; illustrious;
        renowned; stately; splendid; magnificent; grand;
        magnanimous; generous; liberal; free.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Helium \He"li*um\ (h[=e]"l[i^]*[u^]m), n. [NL., fr. Gr. "h`lios
   the sun.] (Chem.)
   An inert, monoatomic, gaseous element occurring in the
   atmosphere of the sun and stars, and in small quantities in
   the earth's atmosphere, in several minerals and in certain
   mineral waters. It is obtained from natural gas in industrial
   quantities. Symbol, He; atomic number 2; at. wt., 4.0026
   (C=12.011). Helium was first detected spectroscopically in
   the sun by Lockyer in 1868; it was first prepared by Ramsay
   in 1895. Helium has a density of 1.98 compared with hydrogen,
   and is more difficult to liquefy than the latter. Chemically,
   it is an inert noble gas, belonging to the argon group, and
   cannot be made to form compounds. The helium nucleus is the
   charged particle which constitutes alpha rays, and helium is
   therefore formed as a decomposition product of certain
   radioactive substances such as radium. The normal helium
   nucleus has two protons and two neutrons, but an isotope with
   only one neutron is also observed in atmospheric helium at an
   abundance of 0.013 %. Liquid helium has a boiling point of
   -268.9[deg] C at atmospheric pressure, and is used for
   maintaining very low temperatures, both in laboratory
   experimentation and in commercial applications to maintain
   superconductivity in low-temperature superconducting devices.
   Gaseous helium at normal temperatures is used for buoyancy in
   blimps, dirigibles, and high-altitude balloons, and also for
   amusement in party balloons.
   [Webster 1913 Suppl. +PJC]

WordNet (r) 3.0 (2006):

helium
    n 1: a very light colorless element that is one of the six inert
         gasses; the most difficult gas to liquefy; occurs in
         economically extractable amounts in certain natural gases
         (as those found in Texas and Kansas) [syn: helium, He,
         atomic number 2]

The Elements (07Nov00):

helium
Symbol: He
Atomic number: 2
Atomic weight: 4.0026
Colourless, odourless gaseous nonmetallic element. Belongs to group 18
of
the periodic table. Lowest boiling point of all elements and can only be
solidified under pressure. Chemically inert, no known compounds.
Discovered in the solar spectrum in 1868 by Lockyer.