expression, godan verb (-tsu)
put an end to; bring to a close; close the books on
Idiomatic expression literally meaning 'to put a period/full stop'. Used figuratively for decisively ending a situation, relationship, or activity. Often implies a final, irreversible conclusion.
長い議論に終止符を打つ時が来た。
It's time to put an end to this long debate.
He put an end to his political career with that scandal.