The letter "w" is the 23rd letter of the English alphabet. It is a consonant and is pronounced as "double-you." In the English language, "w" can represent various sounds, often found in words like water, wonder, and window. In addition to its use in English, "w" is also used in other languages and has different pronunciations. In the context of mathematics, "w" can represent a variable or a specific value. The letter is also commonly used in internet addresses, such as www for World Wide Web.