The use of the letter x as a mathematical unknown is a relatively modern convention. Algebra has been around for a lot longer. Daryl Benson/Stockbyte via Getty Images You might be most familiar with x ...

The letter “x” often symbolizes something unknown, with an air of mystery that can be appealing. Illustration by Meilan Solly Even though “x” is one of the least-used letters in the English alphabet, ...

One little letter, so much baggage. By Stella Bugbee The letter has its obvious appeals. X is a versatile shape — one of the few capital letters to remain symmetrical whether bisected vertically or ...

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For starters, the swastika X—or cross—has come to symbolize the very essence of evil. And the letter, as signified by the skull and crossbones, portrays death by poison. Yet it also represents virtue ...

Peter Schumer does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...