This is the 63rd most frequent Finnish word.
perjantaina
"Perjantaina" means "on Friday" in English.
The word 'perjantaina' specifies the day of the week, indicating 'on Friday'.
Tapaan ystäväni perjantaina.
I will meet my friend on Friday.
Here, 'perjantaina' demonstrates a generalized statement about regular occurrences on Fridays.
Perjantaina sataa usein.
It often rains on Fridays.
In this case, 'perjantaina' sets the time frame for an event happening specifically on Friday.