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helium

American  
[hee-lee-uhm] / ˈhi li əm /

noun

  1. an inert, gaseous element present in the sun's atmosphere and in natural gas, and also occurring as a radioactive decomposition product, used as a substitute for flammable gases in dirigible balloons. He; 4.0026; 2; density: 0.1785 grams/liter at 0°C and 760 millimeters pressure.


helium British  
/ ˈhiːlɪəm /

noun

  1. a very light nonflammable colourless odourless element that is an inert gas, occurring in certain natural gases: used in balloons and in cryogenic research. Symbol: He; atomic no: 2; atomic wt: 4.002602; density: 0.1785 kg/m³; at normal pressures it is liquid down to absolute zero; melting pt: below –272.2°C; boiling pt: –268.90°C See also alpha particle

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

helium Scientific  
/ hēlē-əm /
  1. A very lightweight, colorless, odorless element in the noble gas group. Helium occurs in natural gas, in radioactive ores, and in small amounts in the atmosphere. It has the lowest boiling point of any substance and is the second most abundant element in the universe. Helium is used to provide lift for balloons and blimps and to create artificial air that will not react chemically. Atomic number 2; atomic weight 4.0026; boiling point −268.9°C; density at 0°C 0.1785 gram per liter.

  2. See Periodic Table


helium Cultural  
  1. A chemical element, usually found in the form of a gas, in which two electrons are in orbit, and the nucleus consists of two protons and two neutrons. Its symbol is He.


Word History

The second most abundant element in the universe after hydrogen, Helium (symbol He) is a colorless, odorless, nonmetallic gas that is produced abundantly by the nuclear fusion in all stars and is found in smaller amounts on Earth. It was discovered by the British scientist—and founding editor of the journal Nature—Joseph Norman Lockyer in 1868, while he was studying a solar eclipse with a spectroscope, an instrument that breaks light up into a spectrum. If an element is heated up enough to glow, the emitted light produces a unique spectrum when refracted through a prism. Lockyer noticed that the spectrum of the Sun's corona, which is visible only during a solar eclipse, contained lines produced by an unknown element. He named the element helium from helios, the Greek word for “sun.” Helios gives us many other words pertaining to the Sun, such as heliocentric and perihelion.

Discover More

Because it is lighter than air, helium is used to fill balloons.

Helium is the best known of the inert gases.

Etymology

Origin of helium

First recorded in 1875–80; from New Latin, from Greek hḗli(os) “the sun” + New Latin -ium noun suffix; -ium

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Similarly stranded are shipments of fertilizer, aluminum, steel and helium.

From The Wall Street Journal

It’s focused on helium-3 to start with, since the gas is rare on the Earth but expected to be found in greater abundance on the moon.

From MarketWatch

Moreover, fears of a shortage of helium have also raised alarm in the semiconductor industry.

From MarketWatch

For many current semiconductor cooling applications, helium has no easy substitute.

From The Wall Street Journal

Industries that rely on items such as fertilizer to grow food or helium to make computer chips are suffering from shortages.

From The Wall Street Journal