card catalog

US /ˈkɑːrd ˌkæt̬.əl.ɑːɡ/
UK /ˈkɑːrd ˌkæt̬.əl.ɑːɡ/
"card catalog" picture
1.

a catalog of books or other library materials, arranged on cards in drawers, now largely superseded by the online catalog

:
Before computers, librarians used a card catalog to find books.
The old library still has a beautiful wooden card catalog.