B2to open something, especially a door that is locked (= fastened with a lock) using a key or an electronic device: I keep worrying that I've left the garage door unlocked.Unfastening and openingunlock the mystery/secret of sth›to discover important new facts about something: A chemical has been discovered that may be the key to unlocking the mysteries of Parkinson's disease.Finding and discoveringunlock the imagination›to make the imagination more active, producing interesting ideas and images: One of poetry's functions is to somehow unlock the imagination.Affecting and influencing