keymarker
nounUK /ˈkiːˌmɑːkə/
US /ˈkiːˌmɑːrkər/
A keymarker is a small thing that shows you where a key goes.
She put a red keymarker on her house key so she could find it fast.
OTHER MEANINGS
2. A mark or symbol used to point out an important part of a map or chart.
The keymarker on the map showed where the treasure was hidden.
3. A person or tool that marks items for sorting or identification.
The keymarker labeled every box before the move.
4. A highlight or bookmark used to remember a place in a book or document.
He used a keymarker to save his spot in the story.