This is the 47th most frequent Finnish word.
osa
"Part" or "portion."
Here, 'osa' refers to a component or piece of a whole, specifically a machine.
Tämä koneen osa on rikki.
This part of the machine is broken.
In this context, 'osa' means a segment or act, indicating a division within a larger work, such as a play.
Näytelmän toinen osa esitetään huomenna.
The second part of the play will be performed tomorrow.
In this sentence, 'osa' is used to denote a portion or share of something, specifically responsibility.