Reverse Solidus \

The Reverse Solidus 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+005C in the Universal Character Set.

The reverse solidus (backslash) is used as an escape character in most programming languages, file path separator in Windows, and in regular expressions. Its role as an escape character makes it one of the most important meta-characters in computer science. In LaTeX, it begins every command.

Technical character entities represent brackets, delimiters, and punctuation marks that frequently require escaping in HTML source code and programming contexts. Characters like curly braces, square brackets, pipes, and backslashes often carry special meaning in templating engines, regular expressions, or markup parsers, making their explicit HTML entity encoding important for preventing unintended interpretation by the browser or build tools.

When deciding how to encode the Reverse Solidus 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 backslash entity in HTML content that discusses escape sequences, Windows file paths, regular expressions, or LaTeX commands. The backslash itself may need escaping in JavaScript strings, so using the HTML entity can prevent double-escaping issues in generated content.