Small form of the katakana character オ (o).
- Small combining form of katakana オ (o) used to explicitly specify the vowel part of the previous katakana character, or to show a speaker's pronunciation or extension of that vowel.
- フォ - the sound [ɸo] rather than [ɸu] (フ) or [ho] (ホ)
- シフォン - transliteration of French chiffon
Unlike the hiragana system, used for Japanese language words that kanji does not cover, the katakana syllabary is used primarily for transcription of foreign language words into Japanese and the writing of loan words (collectively gairaigo), as well as to represent onomatopoeias, technical and scientific terms, and the names of plants, animals, and minerals. It is also occasionally used colloquially in some words for emphasis. Names of Japanese companies, as well as certain Japanese language words, are also sometimes written in katakana rather than the other systems. Formerly, female given names were written in katakana. 
- ぉ (hiragana small o)
- オ (full-size o)
- (Katakana) 片仮名; アァ, イィ, ウゥヴ, エェ, オォ, カヵガ, キギ, クグ, ケヶゲ, コゴ, サザ, シジ, スズ, セゼ, ソゾ, タダ, チヂ, ツッヅ, テデ, トド, ナ, ニ, ヌ, ネ, ノ, ハバパ, ヒビピ, フブプ, ヘベペ, ホボポ, マ, ミ, ム, メ, モ, ヤャ, ユュ, ヨョ, ラ, リ, ル, レ, ロ, ワヮ, ヰ, ヱ, ヲ, ン, ー, ヽ, ヾ