master key 
noun
A key that opens several locks, each of which also has its own key: the master key for all the safes in the department...
- The change key will open only that specific lock, while the master key will open that lock and several others in a group.
- She used her master key to open the lock, and began to open the gate.
- I got the master key and opened the door and that's when I saw him in the bath.
- reptile man
- reptile oil
- Reptilia
- reptilian
- reptilian brain
- reptiliary
- reptilious
- reptilism
- reptility
- reptillery
- reptiloid
- Repton, Humphry
- Repub.
- republic
- republical
- republican
- republican calendar
- republican era
- Republican Guard
- republicanise
- republicanism
- republicanization
- republicanize
- republicanized
- republicanizing