Áss or óss means either a member of the family of the æsir (i.e. the Norse gods) or a river mouth.

Stanza from the Icelandic Rune Poem

Áss is aged Gautr*
and prince of Ásgarðr
and lord of Vallhalla.

*Gautr is another name for Oðinn

Stanza from the Norwegian Rune Poem

A river mouth is the way of most journeys;
but a scabbard is of swords.