The letter "Å" is often perceived as an "A" with a ring, interpreting the ring as a diacritic mark. However, the ring is not a diacritic. Rather, the letter developed as a form of semi-ligature of an "A" with a small "O" above it to denote the changed sound value, similar to how the umlaut "¨" is developed from a small "E" written above the letter in question.
In Danish and Norwegian languages, "Aa" is considered equivalent to "Å", in as much as "Aa" is the old spelling, and a fully functional transcription for "Å" when using a foreign typewriter. In surnames, and occasionally in names of geographical places, the old spelling with "Aa" is retained. Correct alphabetisation in Danish and Norwegian places "Aa" along with "Å" as the last letter in the alphabet.
In the Swedish alphabet, "Å" is sorted immediately after "Z", as the third letter from the end. In the Finnish alphabet, the letter is treated just as in Swedish, but its usage is limited to Swedish names. In Norwegian and Danish, "Z" is followed by the sequence "Æ, Ø, Å".
In the Norwegian, Danish and Swedish languages, å is even a word all in itself, meaning a rivulet, a stream or a small river, like the rivers Aa, Au and Aue on the European continent.
In Walloon å was introduced in the beginning of the 20th century, initially to note the same sound as in Danish, that happend in some local variants of eastern-Walloon dialect. Its use quickly spread to all the eastern-Walloon dialects, through the cultural influence of the city of Liège, and covered three different sounds, a long open o, a long closed o, or a long a, depending on the local varieties. The use of a single å letter to cover those different pronunciations has been embraced by the new pan-Walloon orthography, that systemizes a unique orthography for words that are the same, regardless of the local phonetic variations.
In non-standardized writings outside the Liege area, words containing the å letter are written with au, â or ô depending on the pronunciation.
For example the word måjhon (house) in standardized orthography is written môjo, mâhon, mohone, maujon in dialectal writings.
For computers, when using the ISO 8859-1 or Unicode sets, the codes for "Å" and "å" are respectively 197 and 229, or C5 and E5 in hexadecimal. In HTML character entity references, required in cases where the letter is not available by ordinary coding, the codes are Åand å.
The letter "Å" is also used throughout the world as the international symbol for the non-SI unit angstrom, a physical unit of length named after the SwedishphysicistAnders Jonas Ångström. It is always upper case in this context. Unicode also allows code 8491 (U+212B in hexadecimal) when the letter is used specifically as a symbol for the angstrom, giving the sign Å.
