Though the Danish, Norwegian, Swedish and Walloon character Å (å) is derived from an A with a ring, it is considered a distinct letter in those languages. The letter Å is the symbol of the unit ångström, named after the Swedish physicist Anders Jonas Ångström.
The character Ů (ů; a Latin U with overring, or kroužek in Czech Republic) is a grapheme in the Czech language preserved for historic reasons, which identifies a vowel shift. For example, the word for "horse" used to be written kóň, which evolved, along with pronunciation, into kuoň. Ultimately, the vowel [o] disappeared completely, and the uo evolved into ů, modern form kůň. The letter ů now has the same pronunciation as the letter ú (long [uː]), but changes to a short o when a word is morphed (e.g. nom. kůň → gen. koně, nom. dům → gen. domu), thus showing the historical evolution of the language. Ů cannot occur in initial position, however, ú occurs almost exclusively in initial position or at the beginning of a word root in a compound. These characters are used also in Steuer's Silesian alphabet. The [uo] pronunciation has prevailed in some Moravian dialects, as well as in the Slovak language, which uses the letter ô instead of ů.
The ring is used in some dialects of Emilian-Romagnol to distinguish the sound /ʌ/ (å) from /a/ (a).
ů has been used in Old Lithuanian in Lithuania Minor from the 16th till the beginning of the 20th century and for a shorter time in 16th-century Lithuania Major for diphthong [uo].
The ring has been used in the Lithuanian Cyrillic alphabet promoted by Russian authorities in the last quarter of the 19th century with the letter У̊ / у̊ used to represent the /wɔ/ diphthong (now written uo in Lithuanian orthography).
Ring upon e (e̊) is used by certain dialectologists of the Walloon language (especially Jean-Jacques Gaziaux) to note the /ə/ vowel typically replacing /i/ and /y/ in the Brabant province central Walloon dialects. The difficulty of type-writing it has led some writers to prefer ë for the same sound.
Many more characters can be created in Unicode using the U+030A ◌̊ COMBINING RING ABOVE, including the above-mentioned у̊ (Cyrillic у with overring) or ń̊ (n with acute and overring). The standalone (spacing) symbol is U+02DA ˚ RING ABOVE
Although similar in appearance, it is not to be confused with the Japanese handakuten (U+309C ゜ KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK), a diacritic used with the kana for syllables starting with h to indicate that they should instead be pronounced with [p].
- U+030A ◌̊ COMBINING RING ABOVE
- U+00C5 Å LATIN CAPITAL LETTER A WITH RING ABOVE
- U+00E5 å LATIN SMALL LETTER A WITH RING ABOVE
- U+016E Ů LATIN CAPITAL LETTER U WITH RING ABOVE
- U+016F ů LATIN SMALL LETTER U WITH RING ABOVE
- U+212B Å ANGSTROM SIGN
- U+2103 ℃ DEGREE CELSIUS
- U+2109 ℉ DEGREE FAHRENHEIT
Unicode encodes the underring at U+0325 ◌̥ COMBINING RING BELOW
The underring is used in IPA to indicate voicelessness, and in Indo-European studies or in Sanskrit transliteration (IAST) to indicate syllabicity of r, l, m, n etc. (e.g. r̥ corresponding to IPA [ɹ̩]).
- U+1E00 Ḁ LATIN CAPITAL LETTER A WITH RING BELOW
- U+1E01 ḁ LATIN SMALL LETTER A WITH RING BELOW
In Romagnol, e̥ is used to represent /ə/ in diphthongs, e.g. Santarcangelo dialect ame̥ig [aˈməig] ‘friend’, ne̥ud [ˈnəud] ‘naked’. In Emilian, e̥ can be used to represent unstressed /ə/ in very accurate transcriptions.
Half rings also exist as diacritic marks, these are characters U+0351 ◌͑ combining left half ring above and U+0357 ◌͗ combining right half ring above. These characters may be used in the International Phonetic Alphabet, denoting roundedness. They are here given with the lowercase a: a͑ and a͗.
U+1E9A ẚ LATIN SMALL LETTER A WITH RIGHT HALF RING is similar in appearance but differs from a͗ because its compatibility decomposition uses U+02BE ʾ MODIFIER LETTER RIGHT HALF RING instead of U+0357 ◌͗ combining right half ring above.
Other, similar signs are in use in Armenian: the U+0559 ◌ՙ ARMENIAN MODIFIER LETTER LEFT HALF RING and the U+055A ◌՚ ARMENIAN APOSTROPHE.
Unicode also supports U+031C ◌̜ combining left half ring below and U+0339 ◌̹ combining right half ring below.
The ring as a diacritic mark should not be confused with the dot or U+0366 ◌ͦ COMBINING LATIN SMALL LETTER O diacritic marks, or with the degree sign °.