Ö is the 29th and final letter of the Swedish alphabet – unlike German for example, it's a distinct letter and not an accented o.
Note that in Swedish, instead of saying 'A to Z' you say 'A till Ö'. And be aware that of the Scandinavian languages, Swedish and Icelandic are the only ones with the letter ö.
It's also a word in its own right, meaning 'island'. And it happens to be the third favourite Swedish word of The Local's readers.
The letter and word are pronounced the same way, and it can be a tricky sound for non-natives to master at first. Listen to the clip below:
Sweden has a long coastline and many, many lakes, so it's a word you'll hear a lot here.
You'll spot it in place names of course, like Värmdö, Djurö, Älgö, Hönö and Björkö (literally meaning 'hot spring island', 'animal island', 'elk island', 'hen island' and 'birch tree island'). These are generally Sweden's smaller islands, while big ones like Gotland have names without the ö.
This can make things a bit complicated, because you generally use the preposition på with islands. For example, you would say 'jag bor på Värmdö' instead of jag bor i Värmdö. You would usually say 'på Gotland' too, but would say 'i Gotland' if you're talking about Gotland as an administrative region rather than a place – but it's not a major faux pas to mix up på and i.
The word for peninsula is halvö, literally 'half island'.
Ö also features in a Swedish dialectal poem, in a line made up of single letters. You can read the full poem here, and the sentence goes: d’ä e å, å i åa ä e ö. In standard Swedish, that's 'det är en å, och i ån är en ö' (there is a stream, and in the stream there is an island). If that confused you, don't worry – the whole point of the poem is about a city visitor failing to understand the dialect!
Jag bor på en liten ö i skärgården
I live on a small island in the archipelago
Ingen människa är en ö
No man/person is an island