쌓여요 · 쌓였어요 · 쌓일 거예요 · 쌓인 (+noun)
to pile up, to be stacked, to accumulate
Example
밤새 눈이 내려서 길에 많이 쌓였어요.
It snowed all night, so a lot piled up on the roads.
Word parts
Passive of 쌓다 'to pile, to stack'.
Good to know
Pronounced [싸이다]: the ㅎ is silent; common in 스트레스가 쌓이다 'stress builds up'.