ionium

i·o·ni·um

I i

Definitions of ionium word

noun ionium a naturally occurring radioactive isotope of thorium. Symbol: Io; atomic number: 90; atomic weight: 230. 1
noun ionium a naturally occurring radioisotope of thorium with a mass number of 230 0
noun ionium a radioactive isotope of thorium having a mass number of 230 and a half-life of 8 × 104 years 0

before 1905

One of the 15% newest English words

First recorded in 1905-10; ion + -ium

noun

adjective

verb

adverb

pronoun

preposition

conjunction

determiner

exclamation

A common word. It’s meaning is known to most children of preschool age. About 70% of English native speakers know the meaning and use the word.

According to our data most of word are more popular. This word is almost not used. It has a much more popular synonym.

This diagram is provided by Google Ngram Viewer