O, or o, is the fifteenth letter and the fourth vowel letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide.

O, the fourth vowel of the modern alphabet, corresponding to the Semitic ayin, which represented a breathing and not a vowel. The Semitic form may have derived from an earlier sign …

O is used to mean zero, for example when you are telling someone a phone number, or mentioning a year such as 1908.

Noun [edit] o(pluraloes) The name of the Latin-scriptletter O/o. A zero(used in reading out numbers). It is currently two-o-five in the afternoon (2:05 PM). The first permanent English …

O, o (oʊ) n., pl. O's Os, o's os oes. 1. the 15th letter of the English alphabet, a vowel. 2. any spoken sound represented by this letter.

Definition of O noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

O, o meaning: 1. the 15th letter of the English alphabet 2. used in speech to mean zero: 3. used when talking to…. Learn more.

“O'.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/o%27. Accessed 3 Dec. 2025.

O Cinema is an independent, community-based, mission-driven, nonprofit art house cinema in Miami-Dade County and the Beaches featuring first-run films & events.

-o is attached to certain nouns and adjectives to form informal nouns or adjectives; these are often used when speaking directly to another: kid + -o → kiddo (= a kid or person); neat + -o → …