A deadbolt lock is a type of lock that is used to secure doors or windows against unwanted intrusion. The lock consists of a cylinder that is placed in a housing and can be turned with a key. A deadbolt lock can be used as an additional security measure on doors or windows that already have another lock, such as a cylinder lock or latch or hook lock. It can also be used as the only lock on a door or window. A deadbolt lock is usually easy to install and operate, but does provide a reasonably high level of security.