actinium
/ækˈtɪniəm/noun
actinium is a noun meaning “A radioactive, metallic chemical element (symbol: Ac) with an atomic number of 89; found in uranium ores” (English Wiktionary, September 2026). It is spelled A-C-T-I-N-I-U-M, and it appears about once in every 23 million words in written English (wordfreq, 2021 data). The plural of actinium is actiniums.
What does actinium mean?
noun
- 1
A radioactive, metallic chemical element (symbol: Ac) with an atomic number of 89; found in uranium ores.
- 2
An atom of this element.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
How do you pronounce actinium?
- /ækˈtɪniəm/
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vealhurl-actinium.wav, LL-Q1860_(eng)-Naomi_Persephone_Amethyst_(NaomiAmethyst)-actinium.wav, Wikimedia Commons (author and licence on each file's page).
Forms of actinium
- actiniums plural
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
How common is actinium?
Actinium appears about once in every 23 million words in written English, the 145,125th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Actinium in Spanish, French, German and Portuguese
In the sense chemical element:
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does actinium come from?
Borrowed from French actinium. actin- + -ium.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).