helium

[ hee-lee-uhm ]

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

/ 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

helium

/ hē′lē-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

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.

Notes

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

Helium is the best known of the inert gases.

Word History and Origins

Origin of helium¹

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

Word History and Origins

Origin of helium¹

C19: New Latin, from helio- + -ium ; named from its having first been detected in the solar spectrum

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.

Example Sentences

The Moon contains minerals, including rare earths, metals like iron and titanium - and helium too, which is used in everything from superconductors to medical equipment.

From BBC

Now behind the counter where there used to be a vat of loose dirty potatoes sits a neat row of greeting cards, wrapping paper and helium balloons.

From BBC

While the lunar terrain looks rather barren, it contains minerals, including rare earths, metals like iron and titanium - and helium too, which is used in everything from superconductors to medical equipment.

From BBC

The flight had been scheduled to launch Aug. 26 but was initially delayed by a leak in a launch-pad hose that pumps helium into the SpaceX Falcon 9 rocket that sent the Crew Dragon into orbit.

From Los Angeles Times

During the flight it experienced a number of problems, including leaks of helium - which is used in its propulsion system - and issues with several of its thrusters.

From BBC