I couldn’t think of a suitable word starting with X. And I became even more desperate after consulting my dictionary.

~ xerox ~ Xmas ~ x-ray ~ xylograph ~ xylophone ~

Instead of opening a bigger dictionary, I have started to think how and where are we using X. X marks a treasure on a map. We used X to sign documents in the dark ages of illiteracy. Now, in the age of text-language,  X stands for kiss and is often used as a substitute or abbreviation (as in the dictionary entry Xmas). And we are still happily making decisions by penning x inside neat boxes on ballot papers. In mathematics it represents the unknown value, although the Romans may argue that in fact the value is ten. It features in extremes and extras and its triple form advertises adult themes. It even has a chromosome and rays named after it. X is something special.

X in the A to Z challenge.