This is the 415th most frequent Finnish word.
kilometriä
"Kilometriä" means "kilometers" (partitive plural form) in English.
Here 'kilometriä' is part of the quantifying accusative case to indicate distance traveled.
Matkustin viisikymmentä kilometriä autolla eilen.
I traveled fifty kilometers by car yesterday.
In this example, 'kilometriä' quantifies the distance covered collectively in a competitive event.
Maratoonarit juoksivat yhteensä sata kilometriä kilpailussa.
The marathon runners ran a total of one hundred kilometers in the race.
Here 'kilometriä' is used to denote an approximate measurement of length in a statement of distance.