This list covers 5 four letter words that start with X, running alphabetically from “Xmas” to “Xian.” These words range from everyday shorthand you’ll spot in texts and greeting cards to older terms tied to ancient architecture and modern medical imaging. You’ll find them in casual writing, informal speech, and even a few specialized settings, making this a handy reference no matter where you run into an unfamiliar X word.

Four letter words are short terms made up of exactly four letters, and the ones starting with X are especially rare since so few English words begin with that letter. Many of them are informal abbreviations rather than “proper” dictionary staples, like “Xmas” standing in for Christmas since medieval times, when the Greek letter chi (X) was used to represent Christ. That history is part of why X words often carry a casual, shorthand feel even today.

Below you’ll find the table with the word, part of speech, definition, example usage, and description for each entry.

Word: the exact four letter term starting with X, so you can quickly scan the full list and spot the one you’re looking for.

Part of Speech: tells you whether the word functions as a noun, verb, interjection, or another grammatical role, which helps you use it correctly.

Definition: a plain explanation of what the word means, giving you a fast way to understand it without looking elsewhere.

Example Usage: a short sentence showing the word in context, so you can see how it’s naturally used in everyday writing or speech.

Description: extra background on where the word comes from or how it’s typically used, giving you a deeper sense of its meaning and history.

Four letter words

WordPart of SpeechDefinitionExample Usage
XmasNounAn informal shortened spelling of “Christmas,” using the letter X to stand in for “Christ”“We’re hosting a big Xmas dinner this year.”
XrayNounA type of high-energy electromagnetic radiation used to see inside solid objects, such as bones“The dentist took an xray of my tooth.”
XoxoInterjectionA written sign-off meant to represent hugs and kisses“Talk soon, xoxo!”
XystNounA long, covered portico or garden walkway used for exercise in ancient Greece and Rome“Philosophers strolled the xyst while debating ideas.”
XianNounAn informal shorthand for “Christian”“He described himself online as a laid-back Xian.”

Descriptions

Xmas
A widely used informal abbreviation for Christmas, common on cards, signs, and casual writing.
Xray
Usually hyphenated as X-ray, this solid four-letter form shows up in informal and phonetic-alphabet use; it refers to the radiation used in medical and security scans.
Xoxo
A casual, affectionate sign-off popular in texts, emails, and cards, where X stands for a kiss and O for a hug.
Xyst
An old architectural term for a sheltered walkway, originally used by ancient athletes and thinkers for exercise and conversation.
Xian
A casual, sometimes irreverent abbreviation for “Christian,” often seen in social media bios and informal writing.
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