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ACTINIUM
Definition of ACTINIUM
noun
A radioactive, metallic chemical element (symbol: Ac) with an atomic number of 89; found in uranium ores. An atom of this element.
Wiktionary · CC BY-SA
Other senses
ACTINIUM carries 4 further meanings.
noun
A radioactive element found in uranium ores, used in equilibrium with its decay products as a source of alpha rays. Its longest lived isotope is Ac-227 with a half-life of 21.77 years. Atomic number 89; melting point 1,050°C; boiling point 3,198°C; specific gravity (calculated) 10.07; valence 3. cross-reference: Periodic Table.
noun
A supposed chemical element found associated with zinc. Its chemical and physical properties have not been fully investigated.
noun
A radioactive substance found by Debierne to exist in the residues remaining from pitchblende after the extraction of the uranium: a new radio-element closely related in its chemical behavior to lanthanum, from which it has not as yet been found possible to separate it completely.
noun
A supposed metal, said by Phipson to be contained in commercial zinc; -- so called because certain of its compounds are darkened by exposure to light.
Where it comes from
Borrowed from French actinium. actin- + -ium.
Etymology via Wiktionary (CC BY-SA).
Word DNA
Line of descent
- French
- English
One recorded step before English.
Deepest traced root
5th
of 59 source languages in OUTLIER
5.3%
of traced words share this origin (4,125)
branch · 12.9% of traced words
How it is built
Same root, ACTINIUM · 2 relatives in the game
OUTLIER scores every word on how unusual it is, and that number is not published. Working it out at the board is the game.
ACTINIUM in OUTLIER
Players have found it on 39 boards so far. 89 players have found it across Outlier's history.
It first turned up on Day 8, 29 May 2026. The most recent board was Day 150, 17 October 2026. Nobody has seen it on a board for 5 days.
First found by a player on Day 8, 29 May 2026.
Built from these letters
ACTINIUM starts with A and ends with M. Sorted, its letters read ACIIMNTU - the shape to hunt for when the grid is scrambled. I appears more than once.
Words that start ACTINI
Its neighbours in the OUTLIER dictionary - shortest first.
Also seen on Day 8
Could you have found ACTINIUM?
OUTLIER is a daily word game. One grid, the same grid for everybody, and the words nobody else spots are the ones that pay. This word was on Day 8 - and most players walked straight past it.
Play today's OUTLIER