I've looked around the internet, but have been unable to find a word, or words, that simplifies the phrase: conversion of letters to visually similar numbers (or vice versa, numbers to letters). For instance, a g becomes 9, or Z becomes 2, i or l becomes 1, etc. I'm sure I've heard someone describe the process previously using a single word, but wouldn't swear under oath.

We tend to use the process for setting up initial passwords and the like, and I would like to use this short term for repeated occurrences of the phrase above in our documentation.

  • 2
    The most visible form of this is l33ts34k (leetspeak, from "elite [hacker]-speak"), but that doesn't really apply to password substitutions. Maybe it should be called serenading, because, you know, that's what tr0ub4dorz did?
    – Dan Bron
    May 9, 2016 at 14:39
  • 1
    @DanBron: Ha! XKCD - should have looked there first! ;o)
    – Paul
    May 9, 2016 at 14:51
  • Transliterate might work too. merriam-webster.com/dictionary/transliteration May 9, 2016 at 14:58
  • @TheIronCheek: I suppose, if I'm already defining the context of the process then that would work. Thanks, Theiron.
    – Paul
    May 9, 2016 at 15:01
  • A tangential comment: Computer security experts advise against using passwords containing common replacement of letters by like-looking numbers. One method of password cracking involves automatically checking the password against a huge list of dictionary words, place names, etc., etc. - and all common replacement of letters by like-looking numbers has already been programmed into the password-cracking software.
    – TrevorD
    May 9, 2016 at 16:22

3 Answers 3


The word you are looking for may be homoglyph [Wikipedia], although it's broader than your visual letter-number similarity.

A few excerpts (reformatted for clarity of presentation):

In orthography and typography, a homoglyph is one of two or more:

  • graphemes [the smallest units of writing in any language],

  • characters [units of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language], or

  • glyphs [elemental symbols within an agreed set of symbols, intended to represent a readable character for the purposes of writing]

with shapes that appear identical or very similar. The designation is also applied to sequences of characters sharing these properties.

Two common and important sets of homoglyphs in use today are the digit zero and the capital letter O (i.e. 0 & O); and the digit one, the lowercase letter L and the uppercase i (i.e. 1, l & I).

  • I think that's close enough to cover it. It is also the reason why there was no number 1 charaters on typewriter keyboards, and why some of our older staff members (years ago) used to cause us grief when entering information into some of our systems...
    – Paul
    Sep 7, 2016 at 8:02

If the system is specifically constructed for ease of encoding and decoding, then it is an example of Memoria Technica

This is a reference to the book by that name by Grey, 1737.

Mr. Grey's memoria technica was designed as an artificial language to remember numbers, as of the eras, or dates of history.

It is a rigorous transcription system that encodes numbers into phonics (whose primary letter looks like the number), and facilitates forming words and phrases that can be decoded to return the number. Several editions are available online, and the later ones are usually easier to read. The different editions also use different transcription matrices.

  • 1
    Wow, you really do learn something new on this site every day. But I think a mnemonic device like a memoria technica is not exactly what OP wants, because the substitution isn't designed to aid memory, but to make guessing the password more difficult for a third party.
    – Dan Bron
    May 9, 2016 at 16:29
  • 1
    The system is backwards to what the OP is asking for. If you want to encode the first 500 digits of pi, it could take a while to construct an easy-to-remember paragraph. But once you have done so, you can decode it on the fly faster than you can write or speak. But as far as passwords are concerned, they may just as well be numbers as letters.
    – Phil Sweet
    May 9, 2016 at 16:51
  • This is an aide de memoir, not a simple word or pair of words that describe the process.
    – Paul
    May 10, 2016 at 8:08


You could describe the process in detail once and then refer back to the process later by using the word "encode".

Something like:

We generate an initial password for the user by encoding their first name. Each letter is translated into a visually similar number (e.g. g becomes 9, Z becomes 2, i or l becomes 1, etc.).

Then later:


  • User enters first and last name
  • User enters chosen username and email address
  • User clicks Submit button to complete setup process
  • System creates first-use password by encoding first name
  • 1
    This is a valid suggestion, and certainly one could describe such transformations as encodings, but I personally hoped there'd be a more specific word for this specific kind of substitution (but then, I'm not OP!).
    – Dan Bron
    May 9, 2016 at 14:54
  • @DanBron: Yes - leetspeak is closer to the mark, and certainly transliteration.
    – Paul
    May 9, 2016 at 15:02

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