Language scripts or transcription schemes that use the dot above a letter as a diacritical mark:
- In some forms of Arabic romanization, ġ stands for ghayn (غ).
- The Latin orthography for Chechen includes ċ, ç̇, ġ, q̇, and ẋ.
- Traditional Irish typography, where the dot denotes lenition, and is called a ponc séimhithe or buailte "dot of lenition": ḃ ċ ḋ ḟ ġ ṁ ṗ ṡ ṫ. Alternatively, lenition may be represented by a following letter h, thus: bh ch dh fh gh mh ph sh th. In Old Irish orthography, the dot was used only for ḟ ṡ, while the following h was used for ch ph th; lenition of other letters was not indicated. Later the two systems spread to the entire set of lenitable consonants and competed with each other. Eventually the standard practice was to use the dot when writing in Gaelic script and the following h when writing in antiqua. Thus ċ and ch represent the same phonetic element in Modern Irish.
- Lithuanian: ė is pronounced as [eː], as opposed to ę, which is pronounced a lower [æː] (formerly nasalised), or e, pronounced [ɛ, æː].
- Livonian uses ȯ as one of its eight vowels.
- Maltese: ċ is used for a voiceless palato-alveolar affricate, ġ for a voiced palato-alveolar affricate, and ż for a voiced alveolar sibilant.
- Old English: In modernized orthography, ċ is used for a voiceless palato-alveolar affricate /t͡ʃ/, ġ for a palatal approximant /j/ (probably a voiced palatal fricative /ʝ/ in the earliest texts), and (more rarely) sċ for a voiceless palato-alveolar fricative /ʃ/ and cġ for a voiced palato-alveolar affricate /d͡ʒ/.
- Polish: ż is used for a voiced retroflex sibilant /ʐ/.
- The Siouan languages such as Lakota, Osage, and Crow sometimes use the dot above to indicate ejective stops.
- In the Canadian Aboriginal Syllabics orthography for the Cree, Ojibwe, and Inuktitut languages, a dot above a symbol signifies that the symbol's vowel should be a long vowel—the equivalent effect using the Roman orthography is achieved by doubling the vowel (ᒥ = mi, ᒦ = mii), placing a macron over the vowel (ᑲ = ka, ᑳ = kā), or placing a circumflex over the vowel (ᓄ = no, ᓅ = nô).
- In Turkish, the dot above lowercase i and j (and uppercase İ) is not regarded as an independent diacritic but as an integral part of the letter. It is called a tittle. I without an overdot is a separate letter.
- In the Rheinische Dokumenta phonetic writing system overdots denote a special pronunciation of r.
- The Ulithian alphabet includes ȧ, ė, and ȯ.[1]
- The ISO 9 (1968) Romanization of Cyrillic uses ė, ḟ, and ẏ.
- In the ISO 259 Romanization of Hebrew, the overdot is used to transcribe the dagesh: ⟨ḃ ḋ ġ ḣ ṁ ṅ ṙ ṡ ṥ ṧ ṩ ṫ⟩; ⟨ẇ⟩ transcribes the shuruk.
- In IAST and National Library at Calcutta romanization transcribing languages of India, ṅ is used to represent /ŋ/.
- UNGEGN romanization of Urdu includes ṙ.[1]
- In the Venda language, ṅ is used to represent /ŋ/.
- Some countries use the overdot as a decimal mark.
- The overdot is also used in the Devanagari script, where it is called anusvara.
In mathematics and physics, when using Newton's notation the dot denotes the time derivative as in . In addition, the overdot is one way used to indicate an infinitely repeating set of numbers in decimal notation, as in , which is equal to the fraction 1⁄3, and or , which is equal to 1⁄7.