The O with two dots on top is one of the most recognisable accented letters, and also one of the most misunderstood. Depending on the language, those two dots are called an umlaut or a diaeresis, and while they look identical they do quite different jobs. This guide explains both, and shows how to type Ö on any device.
One Character, Two Names
The two dots over an O are a single Unicode character, U+00D6 for the capital and U+00F6 for the lowercase. There is no separate umlaut O and diaeresis O; the same glyph serves both purposes. What changes is the reason the dots are there, and that depends entirely on the language.
The Umlaut
In German, Swedish, Turkish and several other languages, the two dots mark an umlaut, which is a genuine change of vowel sound. The Ö is not an O with decoration; it is a distinct vowel, roughly the sound in the English word her without the r. In German the mark grew out of a small letter e once written above the vowel, which is why an umlaut can sometimes be spelled out as oe when the character is unavailable.
In German, ö and oe are understood as the same sound, so a form that rejects the accented character will usually accept oe as a fallback. In Swedish and Turkish, ö is simply its own letter in the alphabet.
Where The Umlaut Appears
You will meet Ö in German words such as schön and Köln, in Swedish words like för and öl, and in Turkish words like göz. In each language it counts as a full letter with its own place in the alphabet, not a variant of O.
The Diaeresis
In a handful of other languages, and occasionally in careful English, the same two dots are a diaeresis. Here they do not change the vowel; they tell the reader to pronounce it separately from the vowel before it, breaking up what would otherwise look like a single sound. The dots in the older spelling of coöperate are a diaeresis, signalling two distinct o sounds.
How To Type Ö
On Windows, the Alt code is Alt 0214 for the capital and Alt 0246 for the lowercase, typed on the numeric keypad. On a Mac, hold Option and U, then press O. On a phone, press and hold the O key and slide to the two dot option. In Word you can type the built in shortcut, and on any UTF-8 web page you can paste the character directly. The simplest route of all is to copy it from the finder.
The Two Dots On Other Letters
The same mark appears on other vowels, giving Ä, Ë, Ï and Ü. Our accented vowel reference lists all of them with their codes.
In Summary
The O with two dots is a single character that acts as an umlaut in German, Swedish and Turkish, where it is a distinct vowel and often a full letter, and as a diaeresis elsewhere, where it splits vowels apart. Type it with Alt 0214, the Mac Option shortcut, a phone long press or a quick copy from the tool.