idiom. Add to word list Add to word list. locked away safely: Her jewelry is securely under lock and key at the bank. If a person, especially a criminal, is under lock and key, they are being kept in a place from which they cannot escape, usually a prison.

Typically the sweethearts' names or initials, and perhaps the date, are inscribed on the padlock, and its key is thrown away (often into a nearby river) to symbolize unbreakable love.

Restricted or 'security keys' were originally designed as a security solution to prevent unauthorised cutting of keys. Usually installed in conjunction with a Master Key System, this would enable the client to maintain complete control over user access ( access control).

If it has teeth on both sides it's for a car, if it's tiny it's for a padlock, if it's regular size it's likely for a door. A house key or residential door key will have a code like "LR-2" or "SR-1" on the head.