U+24C4, Ⓞ
CIRCLED LATIN CAPITAL LETTER O

[U+24C3]
Enclosed Alphanumerics
[U+24C5]

Translingual

Symbol

  1. (phonetics) an unidentifiable/indeterminate obstruent
  2. (phonetics) unidentifiable/indeterminate back vowel

See and ◌⃝ for uses of a letter inside a circle.