This is the 12th most frequent Finnish word.
jälkeen
"Jälkeen" means "after" in English.
The word 'jälkeen' is used to indicate succession in time, meaning 'after' in this context.
Menemme elokuviin illallisen jälkeen.
We are going to the movies after dinner.
In this sentence, 'jälkeen' reveals the timing of an event that happens subsequently in time.
Peli alkaa sateen jälkeen.
The game starts after the rain.
Here, 'jälkeen' again indicates a time sequence, specifying what action follows the other.