The name Onni is a boy's name of Finnish origin meaning "happiness, luck". Onni and is often added to lists like Names That Mean Happy and discussed in our forums with posts like "If I had 8 daughters whose names started with...".
From the experts:
Onni is the Number 1 boy's name in Finland yet largely unknown in the English-speaking world. Its uplifting meaning makes it a plausible possibility if you want to honor your Nordic heritage.