lastkey
nounUK /ˈlɑːstkiː/
US /ˈlæstkiː/
The last key is the final key you press or use.
She pressed the lastkey to finish the game.
OTHER MEANINGS
2. The final item in a list of keys, such as in a database or map.
The program returned the lastkey in the sorted list.
3. A key used to close or lock something for the final time.
He turned the lastkey in the old door before leaving.
4. In music, the final key played in a sequence or piece.
The song ended on its lastkey with a soft chord.