This is the 345th most frequent German word.
ließ
"Ließ" is the past tense of "lassen," meaning "let" or "allowed."
The word 'ließ' here is used as the past tense of 'lassen', meaning to let or leave, indicating that I allowed the window to remain open.
Ich ließ das Fenster offen.
I left the window open.
In this sentence, 'ließ' signifies the action of leaving someone or something (his dog) behind in a certain place (the park).
Er ließ seinen Hund im Park.
He left his dog in the park.
Here, 'ließ' conveys the permission granted for the children to engage in the activity of playing.