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X

X

494 4.5
The 24th letter of the alphabet written as X
  • noun
  • /ɛks/
translation icon : equis
  • Begins and ends with the letter 'x'.
  • X and Y
  • X, Y, Z
  • X-axis

The second one is spelled with an X instead of a CKS.

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Examples

  • Elon Musk changed the name of Twitter to X, that's it, the letter X.

  • So, I mean, it's just X, the letter X.

  • Letters on the side: F as in Frank, X as in X-ray.

  • This time, the X-ray confirms the exciting news.

  • The letter X is often used to mark the spot on maps.

  • In the English alphabet, X comes after W and before Y.

  • The teacher asked us to write our names using the letter X as the starting point.

Synonyms

x
vsX
299 9.1

The 24th letter of the English alphabet often used to mark mistakes or show an unknown value

is the basic alphabet character without focus on symbolic uses

Compounds

X-ray machine
  • Specialized
12 3.3

A machine that uses X rays to take pictures of the inside of the body or of bags

5 3.6

People born between the early 1960s and the late 1970s who come after the baby boomers

Gen X
  • US
4 3.9

People born between the mid-1960s and early 1980s, often in the United States and Canada

X chromosome
  • Specialized
2 3.9

A cell part that carries genes, present once in males and twice in females and affecting traits related to sex

X-ray film
  • Specialized
1 3.0

Special film that records pictures made by X-rays to show bones or the inside of objects

X-ray picture
  • Specialized
1 3.0

A picture made with X rays that shows the inside of the body

X-ray diffraction
  • Specialized
1 7.1

A way X-rays scatter from the atoms in a crystal to show its structure

factor X
  • Specialized
7.4

A blood protein that helps form a clot to stop bleeding

regression of y on x
  • Specialized
8.7

A method that predicts the value of y from x using numbers

A way a strong gene on the X chromosome causes a trait in children who inherit it

X-linked gene
  • Specialized
7.1

A gene on the X chromosome that causes traits or disorders passed on by that chromosome

A pattern where a gene on the X chromosome causes males to have a trait and females to be carriers

X-linked SCID
  • Specialized
9.6

Serious immune disease in boys caused by a gene change on the X chromosome that prevents T cells from developing

X-radiation
  • Specialized
5.0

High-energy rays used to make images inside the body

X-OR circuit
  • Specialized
7.8

A circuit that sends a signal when two inputs are different

X-ray photograph
  • Specialized
3.7

A picture of the inside of the body made with X-rays

X-ray photography
  • Specialized
3.8

A way to take pictures of the inside of the body using X-rays

X-ray therapy
  • Specialized
3.6

A medical treatment that uses X-rays to kill cancer cells

X-ray tube
  • Specialized
4.0

A tube with no air that makes X rays when fast electrons hit metal

X-SCID
  • Specialized
9.9

A serious inherited disease in baby boys that stops their immune system working

X-tail
  • Specialized
9.8

A tail design for an aircraft with four moving parts in an X shape that help control its direction

Surface Forms

X singular
Xs plural

Etymology

X is the 24th letter of the alphabet. Its shape comes from an old Greek letter called chi, which looked like an X, and that is why we still write X and see it at the start of words like xylophone.