cerradura
/θeraˈduɾa/ · B1 · noun · f
lock
🔒 cerrar (to close) + -dura = the thing that keeps a door closed
Cerrar means to close, as in cerrar la puerta. The suffix -dura names a tool or result, like the English -ure. So a cerradura is the closer: the lock that keeps a door shut. Same family: cerrado means closed.