Helium

Part of speech: noun

Pronunciation: /ˈhiː.li.əm/

Definitions

1. A lightweight, colorless, and odorless gas that is less dense than air and is widely employed in balloons and airships
2. An inert gas belonging to the noble gases group, recognized for its chemical stability and applications in fields like cryogenics and aerospace
3. A chemical element represented by the symbol He and atomic number 2, notable for being the second most abundant element in the universe and used commonly to fill balloons because it is lighter than air

Etymology: Helium was first detected not on Earth but in the Sun. In 1868, astronomers studying a solar eclipse spotted a bright yellow spectral line that matched no known element, and the English astronomer Norman Lockyer concluded that it came from an unknown substance in the Sun's atmosphere. He named it after the Greek word for sun, "hēlios," and the name stuck when the gas was finally isolated on Earth decades later. The name's ending is the surprise. Elements discovered in the nineteenth century were overwhelmingly metals, and their names usually closed with "-ium," so the suffix reads like a metal's label. Helium is a nonmetallic gas, and the ending was a case of an astronomer following a pattern without the chemists' conventions behind it. The historian William Jensen argued that Lockyer, being an astronomer, was probably unaware of those usual chemical naming habits.