Os is the vowel sound “oh”
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
Os, the rune of the Mouth, is a sign for communication, speech and language. I always consider this to the rune of Odhinn, as the Galdrfadr (the father of spells) and his powers and abilities within that sphere, but also as the power of communication in general. You might find that people are calling you, but now is a good time to also reach out to others. Of course, if you are getting text message, phone calls, emails and messages from others all at once, it might be a little overwhelming. Try to handle them one at time.