Thin Space  

The Thin Space character ( ) is a standard HTML entity defined in the HTML specification. In HTML source code, it can be written using the named entity reference  , the decimal numeric character reference  , or the hexadecimal numeric reference  . The character is assigned Unicode code point U+2009 in the Universal Character Set.

The thin space is a narrow whitespace character, typically one-fifth to one-sixth of an em wide. It is used in fine typography to add subtle spacing between certain character combinations. In many European typographic traditions, a thin space precedes punctuation marks like semicolons and question marks.

Punctuation and whitespace entities are among the most frequently used HTML entities in web development. They handle characters that either have special meaning in HTML syntax — such as angle brackets and ampersands — or represent typographic characters that improve the visual quality of text, like em dashes and curly quotes. Proper use of punctuation entities is essential for producing valid, well-formed HTML documents and achieving professional-looking typography on the web.

When deciding how to encode the Thin Space character in your HTML documents, the named entity   is generally the most readable choice for developers reviewing or maintaining source code. The decimal form   and hexadecimal form   are equally valid alternatives that work in contexts where named entities may not be supported, or when generating HTML output programmatically from server-side code. All three representations produce identical visual output in every modern web browser.

Use the thin space between grouped digits in large numbers (10 000), around em dashes, between nested quotation marks, and before certain punctuation marks in French typography. It provides a subtle visual separation that improves readability without creating a full word break.