U+1E51 "ṑ" Latin Small Letter O with Macron and Grave Unicode Character

U+1E51 "ṑ" Latin Small Letter O with Macron and Grave is a precomposed character used primarily in Latin script orthographies, notably in the transcription of certain languages such as Old Church Slavonic or in scholarly linguistic notation, where it represents the vowel "o" modified by both a macron (indicating a long or high tone) and a grave accent (often denoting a falling tone or a specific stress pattern). It is an extension of the basic Latin alphabet with combined diacritical marks, and its usage helps ensure precise phonetic representation in historical or phonetic contexts.