Where does “kolmospesä” come from?

kolmospesä (Finnish) comes from Finnish kolmonen, from Finnish kolme, from Finnish kolmi, from Proto-Uralic *kolme.

kolmospesä (Finnish): third base

Definitions

Step	Language	Word	Meaning
1	Finnish	kolmonen	three; third gear; trey
2	Finnish	kolme	three
3	Finnish	kolmi	tri-
4	Proto-Uralic	*kolme	—

kolmospesä — Etymology, Origin & Word History | Etymology Explorer