This is the 15215th most frequent Russian word.
попало
"Попало" means "ended up" or "hit (a target)."
In this sentence, 'попал' (past tense, masculine form) is used to express 'to find oneself' in a certain state or situation by accident.
Он случайно попал в неприятности.
He accidentally got into trouble.
Here, 'попал' indicates an action of hitting or reaching a target, in this case, the window.
Мяч попал в окно.
The ball hit the window.
In this context, 'попал' is used metaphorically to mean that something is accurate or appropriate.