Æ (lowercase: æ) is a character formed from the letters a and e, originally a ligature representing the Latin diphthong ae. It has been promoted to the status of a letter in some languages, including Danish, Norwegian, Icelandic, and Faroese. It was also used in Old Swedish before being changed to ä. Today, the International Phonetic Alphabet uses it to represent the "a" sound as in the English word cat. Diacritic variants include Ǣ/ǣ, Ǽ/ǽ, Æ̀/æ̀, Æ̂/æ̂ and Æ̃/æ̃.[note 1]

As a letter of the Old English Latin alphabet, it was called æsc, "ash tree,"[1] after the Anglo-Saxon futhorc rune ᚫ which it transliterated; its traditional name in English is still ash, or æsh if the ligature is included.

Latin

In Classical Latin, the combination AE denotes the diphthong [ae̯], which had a value similar to the long i in fine as pronounced in most dialects of Modern English.[2] Both classical and present practice is to write the letters separately, but the ligature was used in medieval and early modern writings, in part because æ was reduced to the simple vowel [ɛ] during the Roman Empire. In some medieval scripts, the ligature was simplified to ę, an e with ogonek, called the e caudata (Latin for "tailed e"). That was further simplified into a plain e, which may have influenced or been influenced by the pronunciation change. However, the ligature is still relatively common in liturgical books and musical scores.
French

In the modern French alphabet, æ (called "a e-dans-l'a") is used to spell Latin and Greek borrowings like curriculum vitæ, et cætera, ex æquo, tænia, and the first name Lætitia. It is mentioned in the name of Serge Gainsbourg's song Elaeudanla Téïtéïa, a reading of the French spelling of the name Lætitia: "L, A, E dans l'A, T, I, T, I, A."[citation needed]
English
The name Ælfgyva, on the Bayeux Tapestry.

In English, usage of the ligature varies between different places and contexts, but it is fairly rare. In modern typography, if technological limitations make the use of æ difficult (such as in use of typewriters, telegraphs, or ASCII), the digraph ae is often used instead.

In the United States, the issue of the ligature is sidestepped in many cases by use of a simplified spelling with "e," as happened with œ as well. Usage, however, may vary; for example, medieval is now more common than mediaeval (and the now old-fashioned mediæval) even in the United Kingdom,[3] but archaeology is preferred over archeology, even in the US.[4]

Given their long history, ligatures are sometimes used to show archaism or in literal quotations of historic sources; for instance, in those contexts, words such as dæmon and æther are often so spelled.

The ligature is seen on gravestones of the 19th century, short for ætate ("at the age (of)"): "Æ xxYs, yyMs, zzDs." It is also common[citation needed] in formal typography (invitations, resolutions, announcements, and some government documents); for example, the Court Circular has continued to use the spelling orthopædic[5] well into the 21st century.

In numismatics, "Æ" is used as an abbreviation for "bronze,"[6] derived from the Latin aes (aere in the ablative, "from bronze").

In Old English, æ represented a sound between a and e (/æ/), very much like the short a of cat in many dialects of Modern English. If long vowels are distinguished from short vowels, the long version /æː/ is marked with a macron (ǣ) or, less commonly, an acute (ǽ).