This is the 751st most frequent Latvian word.
piektdien
"Piektdien" means "on Friday" in English.
Here, 'piektdien' acts as a time designation, specifying the day on which the action will take place.
Es strādāšu piektdien.
I will work on Friday.
In this sentence, 'piektdienas' is used in its plural form to refer to all Fridays as a concept.
Piektdienas ir manas iecienītākās dienas nedēļā.
Fridays are my favorite days of the week.
Once again, 'piektdien' functions as a specific reference to a day when the suggested meeting will be.