Ø
The "Ø" (minuscule: "ø") is a vowel and a letter used in the Danish, Faroese and Norwegian alphabets.
The origin of the letter is a ligature for a diphthong spelled "oe" (the horizontal line of the "e" being written across the "o") that has become a letter in itself. In modern Danish, Faroese and Norwegian, the letter is a monophthongal close-mid front rounded vowel, the IPA symbol for which is also [ø]. To English speakers, the vowel it sounds most like is the vowel in "bird" or "hurt" [1].
The name of the letter is the same as the sound it makes. It is neither a diphthong, a ligature, nor a variant of the letter "O". Though not its native name, among English-speaking typographers the symbol may be called a "slashed o". As one Norwegian tour guide put it, "It's not an 'O' with a slash, it's an 'Ø'!"
In the Turkish, Azerbaijani, Turkmen, Tatar, Finnish, Swedish, Icelandic, German, Estonian, and Hungarian alphabets, the letter "Ö" is the equivalent. Cyrillic alphabet has "Ө" as the equivalent letter, which are used in the Cyrillic alphabets for Kazakh, Mongolian, Azerbaijani etc.
In Danish (and the more conservative Riksmål Norwegian) spelling, ø is a word in itself and it means "island".
The symbol "ø" is also used in the International Phonetic Alphabet to indicate the sound of the Danish and Norwegian letter, the close-mid front rounded vowel.
For computers, when using the ISO 8859-1 or Unicode sets, the codes for 'Ø' and 'ø' are respectively 216 and 248, or D8 and F8 in hexadecimal. On the Apple Macintosh operating system it can by typed by pressing the [Option] key then typing O or o. On Microsoft Windows it can by typed by holding down the [Alt] key while typing 0216 or 0248 on the numeric keypad, provided the system uses code page 1252 as system default. The Unicode letter name is "Latin capital/small letter O with stroke". In HTML character entity references, required in cases where the letter is not available by ordinary coding, the codes are Ø and ø. In the X Window System environment, one can produce these characters by depressing the Multi key with a slash and then striking an o or O. In some systems, such as older versions of MS-DOS, the letter Ø is not part of the default codepage. In this case, unless additional codepages (such as the Scandinavian ones) are installed, a yen sign (¥) replaces Ø, while a ¢ sign replaces ø.
The non-existing letter Ø-with-umlaut is used by the Danish and Swedish national railways in pictograms marking trains crossing the Øresund (da)/Öresund (sv) Bridge between the nations.
The ø is used in the fictional language Bork Bork Bork.
References
- Robert Bringhurst (2002). The Elements of Typographic Style, pp. 270, 284. For typographic reference to "slashed o".