Latin Capital Letter W
Literally named 'double U' in English — and 'double V' in French, Spanish, and several other languages — uppercase 'W' is the only Latin letter whose name describes a ligature origin rather than its own sound. It sits at ASCII code point 87 (0x57), exactly 32 below its lowercase counterpart 'w' at 119 (0x77), maintaining the single-bit case offset (bit 5) shared by all ASCII A–Z / a–z pairs. Despite moderate frequency in running English text, 'W' dominates everyday visibility as the triple-repeated lead of every World Wide Web URL.
Technical Details
Code Example
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// Wide character typewchar_t wc = L'W'; // Wide characterwprintf(L"Wide char: %lc\n", wc);
Common Usage
Web and protocol ubiquity: The prefix 'www' makes 'W' one of the most visually repeated uppercase letters in digital life, appearing in URLs, browser interfaces, and documentation. In spoken form, 'double-u double-u double-u' is famously the longest-to-pronounce three-letter sequence in English — nine syllables for three characters — which drove the informal spoken shorthand 'dub-dub-dub' in early web culture.
Regex word boundary and metacharacter: In most regex engines, \w matches a 'word character' — typically [A-Za-z0-9_] in ASCII mode, though Unicode-aware engines extend this to include letters from other scripts. The uppercase form \W matches the complement (any non-word character). This makes 'W'/'w' one of the few letters whose escaped form carries a standard metacharacter meaning across virtually all major regex flavors.
Scientific and engineering symbols: In physics, uppercase 'W' is the SI symbol for the watt (unit of power), named after James Watt, and italic 'W' commonly denotes work or energy in equations — a quantity-versus-unit italic distinction parallel to V/volt. In chemistry, 'W' is the element symbol for tungsten (atomic number 74), derived from its German name Wolfram, making it one of the few element symbols that does not match the English name.
Diacritical variants: Uppercase 'W' has a narrow but notable diacritical family. Ŵ (circumflex) is used in Welsh, where it marks a long vowel sound, and Ẁ and Ẃ (grave and acute) also appear in Welsh orthography. Ẅ (diaeresis) exists in Welsh transliteration contexts. Outside Welsh and a few African language romanizations, accented forms of 'W' are uncommon in Latin-script writing systems.
Web and protocol ubiquity: The prefix 'www' makes 'W' one of the most visually repeated uppercase letters in digital life, appearing in URLs, browser interfaces, and documentation. In spoken form, 'double-u double-u double-u' is famously the longest-to-pronounce three-letter sequence in English — nine syllables for three characters — which drove the informal spoken shorthand 'dub-dub-dub' in early web culture.
Regex word boundary and metacharacter: In most regex engines, \w matches a 'word character' — typically [A-Za-z0-9_] in ASCII mode, though Unicode-aware engines extend this to include letters from other scripts. The uppercase form \W matches the complement (any non-word character). This makes 'W'/'w' one of the few letters whose escaped form carries a standard metacharacter meaning across virtually all major regex flavors.
Scientific and engineering symbols: In physics, uppercase 'W' is the SI symbol for the watt (unit of power), named after James Watt, and italic 'W' commonly denotes work or energy in equations — a quantity-versus-unit italic distinction parallel to V/volt. In chemistry, 'W' is the element symbol for tungsten (atomic number 74), derived from its German name Wolfram, making it one of the few element symbols that does not match the English name.
Diacritical variants: Uppercase 'W' has a narrow but notable diacritical family. Ŵ (circumflex) is used in Welsh, where it marks a long vowel sound, and Ẁ and Ẃ (grave and acute) also appear in Welsh orthography. Ẅ (diaeresis) exists in Welsh transliteration contexts. Outside Welsh and a few African language romanizations, accented forms of 'W' are uncommon in Latin-script writing systems.