Convert words into numeronyms by keeping the first and last letter and replacing the middle with its length. Adjustable minimum word length, optional lowercasing, works on whole sentences.
internationalization becomes i18n, and so does everything else. Type a word or a whole sentence. Each word long enough to benefit keeps its first and last letter, and the letters in between are replaced by their count. Short words are left alone so the result stays readable.
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How a numeronym compresses a word
The i18n pattern
A numeronym is a word abbreviated with a number. The variety used in software follows one rule: keep the first letter, keep the last letter, and replace everything between them with a count of the omitted characters. Internationalization has eighteen letters between the leading i and the trailing n, so it becomes i18n. Accessibility gives a11y, localization gives l10n, and Kubernetes gives k8s.
The convention is usually traced to Digital Equipment Corporation in the 1980s, where staff shortened long internal terms this way, and it spread through open-source projects that needed to name the same handful of unwieldy concepts thousands of times. It stuck because it is mechanical. Unlike an acronym, there is nothing to invent and nothing to remember: given the full word, everyone derives the same abbreviation, and given the abbreviation plus context, a reader can usually recover the word.
Why a minimum length matters
The compression only pays off on long words. Applying the rule to "hello" yields h3o, which saves two characters and costs all recognisability. Worse, short numeronyms collide constantly: dozens of common five-letter words share the same first letter, last letter and length, so the abbreviation stops identifying anything.
That is why this tool has a minimum length, defaulting to five. Words shorter than the threshold pass through untouched, which is what lets you paste an entire sentence and get something still readable. Raising the minimum to eight or ten produces the conservative style you see in practice, where only the genuinely unwieldy terms are abbreviated and the surrounding prose is left alone.
Where they help and where they hurt
Numeronyms work well as jargon among people who already share the vocabulary. In an accessibility team, a11y is faster to type and read than the full word, and the meaning is never in doubt. They also make good identifiers: short, ASCII-safe, unambiguous within a project, and stable enough for package names, directory names and configuration keys.
They fail with newcomers and with search. A reader who has not met the term cannot expand it, and unlike an acronym there is no capital-letter hint that an abbreviation is even happening. Screen readers may pronounce a11y as a sequence rather than a word, and searching documentation for "localization" will not match a page that only ever writes l10n. The practical compromise is the one good documentation already uses: write the full term the first time, put the numeronym in parentheses after it, then use the short form freely.
FAQ
What is a numeronym?
A word abbreviated using a number. In software it means keeping the first and last letters and replacing the middle with the count of omitted letters, as in i18n.
Why is internationalization written i18n?
There are eighteen letters between the initial i and the final n. The same rule gives a11y for accessibility and l10n for localization.
Why does the minimum length default to five?
Below that the abbreviation saves almost nothing and collides with many other words. Five keeps short words readable while still shortening the long ones.
Does it handle accented letters and emoji?
Yes. Counting is done by Unicode code point, so accented characters count as one letter each and emoji are not split into fragments.
What happens to punctuation?
Punctuation around a word is preserved and only the letters are shortened, so "accessibility," keeps its comma and becomes "a11y,".
Should I use numeronyms in code?
They are fine as identifiers within a project that already shares the vocabulary. In documentation, write the full term first and introduce the numeronym in parentheses.