This question is related, but is not a duplicate, of Why do some words have "X" as a substitute?.

I have noticed that a few nouns can be significantly abbreviated with an "x" at the end. Some examples come to mind:

  • Transmit → Tx
  • Receive → Rx
  • Passengers → Pax
  • Tickets → Tix

There are likely others in existence I'm not aware of. Most abbreviated nouns ending in "x" seem to be used only as technical jargon (in this case, Fax, Fax, Transportation, Entertainment, respectively). What is the history of using "x" at the end of a word to severely shorten it? And, does the usage of "x" in this context have a single word to describe it?

  • 1
    Wiktionary has some information and additional examples about "-x" as an abbreviation: en.wiktionary.org/wiki/-x#Suffix_4.
    – geoff
    Mar 8, 2017 at 20:54
  • 5
    Note that X is often used to mean "trans-", as in "Xmit". For "Tix", though, the reason probably is simply the sound similarity.
    – Hot Licks
    Mar 8, 2017 at 21:06
  • X is also used to stand for cross; e.g., LX = lacrosse. There is no special word for abbreviations or initializations ending in X or any other letter AFAIK. It's all part of an inclination to shorten, to leave out what is already known--e.g., here, the OP, ELL. Note that in entertainment FX (not Fax) stands for effects, as in special effects. Also, Rx also means prescription; most acronyms and abbreviations have multiple meanings depending on context.
    – Xanne
    Mar 8, 2017 at 21:47
  • I've always understood pax to stand for (paying) Passengers and (prepaid) Passes in the UK bus industry. In which context the x could be interpreted as a "wildcard" symbol covering both -ssengers and -sses. Mar 8, 2017 at 23:07
  • 1
    I think tickets->tix is a bit different to the other examples because it is a logical abbreviation based on the sound of the letter X being a reasonable substitute for the letters cks. So tickets becomes ticks becomes tix.
    – nnnnnn
    Jul 8, 2021 at 7:12

1 Answer 1


The letter "X" has long been used as a place-holder.

It was once standard for illiterate persons to sign legal documents with an "X".

Mathematicians use the letter "x" quite often as a place-holder.

For example, a mathematician might write, "Ɐ x, y, z ∈ ℝ, (x = y) ⋏ (y =z) ⟹ (x = z)"

It is standard to use an "x" to mean, "replace the x with some other string of symbols".

It is a convention.

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