What does "card index" mean?

Any index formed with index cards, as was common in many businesses before the microcomputer revolution.

What is a synonym for "card index"?

Common synonyms include: card catalog, card catalogue, chart, contents, index, rolodex.

noun

noun ·Rare ·Advanced level

Noun

1
Any index formed with index cards, as was common in many businesses before the microcomputer revolution.
"Near-synonym: card catalogue"
2
an alphabetical listing of items (e.g., books in a library) with a separate card for each item wordnet