Os is the vowel o
Anglo-Saxon Rune Poem (from ragweedforge.com)
The mouth is the source of all language,
a pillar of wisdom and a comfort to wise men,a blessing and a joy to every knight
Today I cast the Os reversed. Os is the translated as “mouth” as that thing which words come out from people. Esoterically, Os is the power of speech and song, everything having to do with voice. It is a rune of wisdom, but also of eloquence. When it is reversed, it shows problems with that area. Communication is misread, words are misheard, phone calls are missed. Try to make do as best as you can, and if you can, think about what you say before you say it, and re-read anything written before you publish it.