o / オ
The last of the five katakana vowels — a steady “oh” built like the kanji 才. Three strokes close out アイウエオ.
Pronunciation
The character オ represents the vowel 'o', identical in pronunciation to hiragana お — like the 'o' in 'oh'. Very common in loanwords, especially those starting with 'o' (office, orange, original).
オ closes the katakana vowel set with the same “o” as hiragana お. It launches a huge share of everyday loanwords: オレンジ (orange), オフィス (office), オープン (open), オリンピック (Olympics). When a long “oh” is needed, katakana adds the bar ー — as in オー.
How to write オ
Trace オ on the canvas at the top of the page. Animated arrows show each stroke's direction; trace along them and the stroke fills in. Each numbered step below explains what that stroke does.
A horizontal stroke across the upper third, left to right.
A long vertical crossing it, descending from the top and curving gently left at the bottom — a soft hook.
A diagonal stroke from the crossing point, sweeping down to the lower left.
Origin
Katakana オ derives from part of the kanji 於 (o) — “at” or “in” — keeping the strokes that resemble 才. Hiragana お comes from the very same 於, but where hiragana rounded the full character, katakana kept only this angular sliver.
Common words starting with オ
Printable practice sheet
Print this worksheet to practice writing オ by hand — the top row shows the stroke order to trace, then fill the blank squares.
Lock it into memory
Reading is only half of it. Drill the katakana you’ve learned with spaced-repetition flashcards — the fastest way to make them stick.