An abstract noun that begins with X is xenophobia, a hatred or fear of foreigners or strangers; a word for a concept.
There is not a word
x like an x ray
Xenon Xylophone Xenophobia X-ray
Latex is a 5 letter word. It begins with L and ends with X.
"Xenophobe" - a person with an irrational fear or hatred of strangers or foreigners.
The word x-ray is a common compound noun. The word Xbox is a proper compound noun.
Xenon is a chemical element. It begins with the letter x.
Xileafón (X is used in loanwords; it's not native to Irish.)
Xianjindao is a volcano in North Korea. It begins with the letter x.
Xhosa, xantaat, xeno, xantien, to name a few.