Plutonium

How to spell plutonium

9 letters · 4 syllables

How to pronounce plutonium

Say the part in capitals loudest.

What does plutonium mean?

1. nounA dense, radioactive metallic element used as fuel in nuclear reactors and weapons.

Plutonium in a sentence

• The reactor was designed to produce plutonium as a by-product.

• Inspectors tracked every gram of plutonium at the facility.

Where does plutonium come from?

Language of origin: Greek

Plutonium takes its name from the planet Pluto, continuing a small naming tradition begun with uranium (after Uranus) and neptunium (after Neptune). The planet itself was named for Pluto, the Roman god of the underworld and of hidden wealth, whose Greek counterpart was Plouton, a name rooted in ploutos meaning 'riches', because the buried minerals of the earth were thought to be his domain. The chemists Glenn Seaborg and his colleagues synthesised the element in 1940 and 1941 at Berkeley, and they chose the name to follow neptunium logically along the sequence of outer planets. The suffix -ium, drawn from Latin, is the standard ending for metallic elements, which is why the spelling keeps the unstressed 'i' before the final 'um'. The fitting twist is that an element famous for its sinister energy carries the name of the god of the dead, and the buried-treasure sense of ploutos survives today in the unrelated-looking word 'plutocracy', rule by the wealthy.

How the word is built

• pluton- (from the planet Pluto)
• -ium (chemical element suffix)