A Key can mean any one of the following:
An old key
Bedobin Copy Key
Black key
Blue key
Bone Key
Brass key
Bronze key
Bunch of keys
Carnillean Key
Cell door key
Chest key
Closet Key
Crystal key
Dusty Key
Front door key
Glough's key
Jail keys
Keep key
Key
Khazard cell keys
Large key
Little key
Magenta key
Maze key
Metal key
Metal Key
Miscellaneous key
Muddy key
Orange Key
Red key
Shiny key
Shiny Key
Silverlight key 1
Silverlight key 2
Silverlight key 3
Sinister key
Wrought iron key
Yellow key