Hi
Don,
Tauno is a name from Karjala (Karelia) in East Finland. It's from the Karelian adjective "tauno" which means "modest, discreet, good-natured".
Sometimes it is used as a Finnish variant of the Latin name Augustinus as well.
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Uno is more often written Uuno in Finland and it comes from the Latin name/word Uno which means "one".
Terveisin,
Satu