O͘



O͘o͘ is one of the six Hokkien vowels as written in the Pe̍h-ōe-jī (POJ) orthography. It is pronounced. Because Hokkien is a tonal language, the standard letter without a diacritic represents the vowel in the first tone, and the other five possible tone categories require one of the following tonal symbols to be written above it:
 * Ó͘ ó͘ (second tone)
 * Ò͘ ò͘ (third tone)
 * Ô͘ ô͘ (fifth tone)
 * Ō͘ ō͘ (seventh tone)
 * O̍͘ o̍͘ (eighth tone)

History
The character was introduced by the Xiamen-based missionary Elihu Doty in the mid-nineteenth century, as a way to distinguish the Hokkien vowels and  (the former becoming $\langleo͘\rangle$). Since then it has become established in the Pe̍h-ōe-jī orthography, with only occasional deviations early in its usage – one example being Carstairs Douglas's 1873 dictionary, where he replaced the $\langleo͘\rangle$ with an o with a curl (similar to that of the English Phonotypic Alphabet), and a second example being Tan Siew Imm's 2016 dictionary of Penang Hokkien, where she replaced the $\langleo͘\rangle$ with $\langleɵ\rangle$.

Computing
In the Unicode computer encoding, it is a normal Latin o followed by, and is not to be confused with the Vietnamese Ơ. This letter is not well-supported by fonts and is often typed as either o· (using the interpunct), o• (using the bullet), o' (using the apostrophe), oo (as used in Tâi-lô for Taiwanese Hokkien and Wāpuro rōmaji for Japanese), or ou (as used in Wāpuro rōmaji for Japanese).