Inverted breve or arch is a diacritical mark, shaped like the top half of a circle ( ̑ ), that is, like an upside-down breve (˘). It looks similar to the circumflex (ˆ), which has a sharp tip (Â â Ê ê Î î Ô ô Û û), while the inverted breve is rounded: (Ȃ ȃ Ȇ ȇ Ȋ ȋ Ȏ ȏ Ȗ ȗ).

Inverted breve can occur above or below the letter. It is not used in any natural language alphabet,^{[citation needed]} but as a phonetic indicator. It is identical in form to the Ancient Greek circumflex.

The inverted breve above is used in traditional Slavicist notation of Serbo-Croatian phonology to indicate long falling accent. It is placed above the syllable nucleus, which can be one of five vowels (ȃ ȇ ȋ ȏ ȗ) or syllabic ȓ. This use of the inverted breve is derived from the Ancient Greek circumflex, which was preserved in the polytonic orthography of Modern Greek and influenced^{[clarification needed]} early Serbian Cyrillic printing through religious literature. In the early 19th century, it began to be used in both Latin and Cyrillic as a diacritic to mark prosody in the systematic study of the Serbo-Croatian linguistic continuum.

In the International Phonetic Alphabet, an inverted breve below is used to mark a vowel as non-syllabic, i.e. assuming the role of a semivowel. The diacritic thus expands upon the four primary symbols [j, w, ɥ, ɰ] the IPA reserves for semivowels, which correspond to the full vowels [i, u, y, ɯ], respectively. Any vowel is eligible for marking as non-syllabic; a frequent use of the diacritic is in conjunction with the centralised equivalents of the vowels just mentioned: [ɪ̯, ʊ̯, ʏ̯].

The same diacritic is placed under iota (ι̯) to represent the Proto-Indo-European semivowel *y as it relates to Greek grammar; upsilon with an inverted breve (υ̯) is used alongside digamma (ϝ) to represent the Proto-Indo-European semivowel *w.^[1]

Inverted breve characters are supported in Unicode and HTML code (decimal numeric character reference).

In LaTeX the control \textroundcap{o} with \usepackage{tipa} puts an inverted breve over the letter o.^[2]

• Tie (typography)

• Diacritics Project — All you need to design a font with correct accents