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YLEM
Definition of YLEM
noun
In the Big Bang theory, the hot and dense plasma that made up the matter in the cosmos following the initial baryogenesis at an early stage of its expansion and cooling, from which the first atoms formed and photons decoupled. The emission of photons in this phase is regarded as the source of the cosmic microwave background.
Wiktionary · CC BY-SA
Other senses
YLEM carries 3 further meanings.
noun
A form of matter hypothesized by proponents of the Big Bang theory to have existed before the formation of the chemical elements.
noun
In the Big Bang theory, the hot and dense plasma of which the cosmos consisted at the time of recombination in an early stage of its expansion and cooling, when the first atoms formed and photons decoupled, the source of the cosmic background radiation.
noun
(cosmology) the original matter that (according to the big bang theory) existed before the formation of the chemical elements
Where it comes from
Resuscitation of Middle English ylem, from Medieval Latin hȳlem, accusative of hȳlē (“matter, the fundamental matter of all things; the matter of the body”) (whence English hyle), a transliteration of Ancient Greek ὕλη (húlē, “wood; material, substance; matter”). The concept of “fundamental matter” – Ancient Greek πρώτη ὕλη (prṓtē húlē) – was propounded by the Greek philosopher Aristotle (384–322 B.C.E.). The term ylem was first used in modern English in the paper “The Origin of Chemical Elements”, coauthored by Russian-American theoretical physicist and cosmologist George Gamow (1904–1968), American cosmologist Ralph Asher Alpher (1921–2007) and German-American nuclear physicist Hans Bethe (1906–2005), published 1 April 1948 in Physical Review. Alpher claimed to have found the word “in a large dictionary”, perhaps Webster’s New International Dictionary (2nd ed., 1934), which he referred to in a second 1948 paper (cited below). In a 1968 interview, Gamow also associated ylem with a Hebrew word he did not name; it remains unclear which word he was referring to. The word ylem reappeared in popular books on science following the discovery in 1964–1965 of the cosmic microwave background, which had been predicted in 1948 by Alpher and Robert Herman (1914–1997), and again after the publication of images of the radiation composed from measurements by two satellites, the Cosmic Background Explorer (COBE) in 1992 and the Wilkinson Microwave Anisotropy Probe (WMAP) in 2003.
Etymology via Wiktionary (CC BY-SA).
Word DNA
Line of descent
6 recorded generations before English.
Deepest traced root
17th
of 59 source languages in OUTLIER
0.7%
of traced words share this origin (552)
branch · 2.1% of traced words
How it is built
Same root, YLEM · 1 relative 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.
YLEM in OUTLIER
Players have found it on 48 boards so far. 69 players have found it across Outlier's history.
It first turned up on Day 33, 22 June 2026. The most recent board was Day 165, 1 November 2026. Nobody has seen it on a board for 1 day.
First found by a player on Day 33, 22 June 2026.
Built from these letters
YLEM starts with Y and ends with M. Sorted, its letters read ELMY - the shape to hunt for when the grid is scrambled. No letter is used twice, which makes it an isogram.
Same letters, different word
3 other words use exactly these letters. Worth knowing at the board: an anagram fits a grid the same way.
Also seen on Day 33
Could you have found YLEM?
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 33 - and most players walked straight past it.
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