from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A large card held out of the audience's sight, bearing words or dialogue in large letters as an aid for a speaker or actor chiefly in television broadcasting.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A card with writing on it, shown to actors to remind them of their lines.
Sorry, no etymologies found.
A teacher handed him a cue card with POTATOE! written on it and then Dan asked a little kid to spell “potato.”