This is the 5017th most frequent Polish word.
postanowili
"Postanowili" means "they decided."
Here 'postanowili' is used to express a firm decision or resolve made by a group of people, commonly indicated by its alignment with a plural subject.
Postanowili spędzić wakacje nad morzem.
They decided to spend their vacation by the sea.
In this sentence, 'postanowiliśmy' (the first-person plural form) illustrates individual resolve or determination within a group, showing flexibility and consideration before acting.
Postanowiliśmy zmienić nasze plany na weekend.
We decided to change our plans for the weekend.
This usage of 'postanowili' emphasizes a conclusive decision reached after deliberation amongst the group of subjects.