The rare daily word game sweeping the globe. Find what's hidden in plain sight.
ISOPRENE
Definition of ISOPRENE
noun
An unsaturated hydrocarbon, C5H8, that is readily polymerized; natural rubber (caoutchouc) is cis-1,4-polyisoprene, and trans-1,4-polyisoprene is present in gutta-percha and balata; it is the structural basis for the terpenes.
Wiktionary · CC BY-SA
Where it comes from
Coined (1860) by British chemist C. G. Williams, from iso- (“equal; different, isomeric”) + pr(op)- (“three carbon prefix”) + -ene (“alkene suffix”). A misnomer.
Etymology via Wiktionary (CC BY-SA).
OUTLIER scores every word on how unusual it is, and that number is not published. Working it out at the board is the game.
ISOPRENE in OUTLIER
Players have found it on 2 boards so far.
It first turned up on Day 40, 29 June 2026. The most recent board was Day 103, 31 August 2026. Nobody has seen it on a board for 8 days.
First ever to find it
on Day 40, 29 June 2026 - before anyone else in Outlier's history. See the Pioneers
Built from these letters
ISOPRENE starts with I and ends with E. Sorted, its letters read EEINOPRS - the shape to hunt for when the grid is scrambled. E appears more than once.
Same letters, different word
2 other words use exactly these letters. Worth knowing at the board: an anagram fits a grid the same way.
Words that start ISOPRE
Its neighbours in the OUTLIER dictionary - shortest first.
Also seen on Day 40
Could you have found ISOPRENE?
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 40 - and most players walked straight past it.
Play today's OUTLIER