But, how was it created? X is derived from the Phoenician letter samekh, meaning “fish.” Originally used by the Phoenicians to represent the /s/ consonant (denoting a hard S sound), the Greeks borrowed the samekh around 900 BC and named it Chi.

Scholars may never know for sure, but some theorize that Descartes chose to make the letter “x” appear often because his printer had a large cache of x’s in stock, as the letter is scarce in the French language.