Question mark

The question mark is a vital punctuation mark used to signal an interrogative clause or phrase. In many languages, it tells the reader that a sentence is asking something rather than making a statement. It is also known by other names, such as the interrogation point, the query, or the eroteme in journalism. Beyond simple questions, the symbol can act as a meta-sign to show uncertainty about a piece of information. This might include doubt about a specific spelling or a deeper truth.

Writing with question marks varies significantly depending on the language and its specific rules. In English, the mark typically appears at the end of a sentence to replace a full stop. It can also appear at the end of a clause or phrase to replace a comma, colon, or semicolon. Spanish uses a more complex system of bracketing. Since 1754, Spanish interrogatives have required both an opening and a closing mark. The sentence begins with an inverted question mark and ends with a standard one.

Other cultures use entirely different shapes and placements for their questions. In Armenian, the question mark is a diacritic called a harakan. It takes the form of an open circle and is placed over the stressed vowel of a question word.

Greek uses a mark that looks like a semicolon. For languages that write from right to left, such as Arabic, Persian, or Urdu, the symbol is mirrored. This mirroring ensures the mark faces the correct direction for the flow of the text.

In East Asian languages like Chinese and Japanese, a fullwidth version of the mark is often used in official writing.

The exact origins of the question mark remain a subject of historical debate. One theory suggests the shape was inspired by the crook in a cat's tail, though Egyptians did not use punctuation. In the fifth century, Syriac Bible manuscripts used a mark called the zagwa elaya. This was a vertical double dot placed over a word at the start of a sentence. By the year 783, a mark known as the punctus interrogativus appeared in the Godescalc Evangelistary. This mark was described as a lightning flash striking from right to left.

Over time, the function and appearance of this lightning flash mark evolved through several stages. Some paleographers believe the original mark might have indicated musical intonation or pitch. By the 10th century, this connection to pitch seemed to be forgotten. The mark was often used at the end of clauses regardless of whether they were questions. In the early 13th century, the growth of universities in cities like Paris led to more organized punctuation. Scholars assigned the lightning flash specifically to interrogative sentences. This process made the stroke more sharply curved, resulting in the modern shape.

In the modern era, the symbol has taken on many specialized typographic forms. The percontation point was invented by Henry Denham in the 1580s for rhetorical questions. It was essentially a reversed question mark that opened away from the sentence. Today, we also see the interrobang, which combines a question mark and an exclamation mark. Other variations include the double question mark or the combination of question and exclamation marks used in chess annotation. These symbols allow writers to express very specific nuances of tone and intent.

In the world of computing, the question mark is a powerful tool with many technical roles. It is represented by ASCII code 63 and Unicode code-point U+003F. In many shell and scripting languages, it acts as a wildcard character. This means it can substitute for any single character in a string of text. In computer programming, the symbol has unique meanings in many different languages. In C-descended languages, it is part of the conditional operator. In languages like Swift and Kotlin, it is used to handle "optional" or "nullable" data types. It even helps computers manage error handling and random number generation.