expresso
Espresso. There is no X. It is not express.
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Wrong: I’ll have an expresso.
Right: I’ll have an espresso.
Italian espresso, meaning pressed out. No X anywhere in it.
Where the X comes from
The Italian espresso means “pressed out”—the water is forced through the grounds under pressure. It shares a root with express but the Italian spelling has no X.
English speakers hear the word, recognise express, and reasonably conclude it must be about speed. It isn’t. It’s about pressure.
The caveat
Expresso appears in some dictionaries as a variant, and it’s been used in English for a century. It is nonetheless the version that gets you a look from anyone who works with coffee.
Now go order it correctly.