This is the 17216th most frequent Polish word.
zagrały
"Zagrały" means "they played" (past tense, feminine or neuter plural).
This usage of 'zagrały' pertains to the past tense of the verb 'grać' (to play), indicating musical performance by the subject (female plural).
Zagrały pięknie na koncercie zespołu.
They played beautifully at the band's concert.
Here, 'zagrały' figuratively means to have taken up or performed a role effectively in an outcome (female plural).
Zagrały główną rolę w naszym sukcesie.
They played a major role in our success.
In this context, 'zagrały' refers to acting or performing in a cinematic production (female plural).