The key tag is used for a variety of different things:
- Relation database keys
- Security keys (ssh, cryptography, etc.)
- Dictionary/map/table/array keys
- License keys
- Physical lock-type keys
- Key strokes from keyboards
It needs sorting out.
I think when it's applying to dictionary/map/table/array keys, the tag should probably just be removed from the question. The question should already be tagged "dictionary" or "array" or similar which should cover it.
The rest should be split into new tags. (If only we then had disambiguation tags - basically tags with a wiki excerpt but which can't be selected. Though now that tag excerpt displays it may be a bit better if it gets a tag wiki.)