Simple Definition of cardboard

from our Learner's Dictionary

cardboard

1 of 2

noun

: a stiff and thick kind of paper that is used especially for making boxes
Cover the windows with cardboard.
a piece of cardboard

cardboard

2 of 2

adjective

1
: made out of cardboard
cardboard boxes
2
: not acting or seeming real : having an obviously false or fake quality
The play had cardboard characters.

Cite this Entry

“Cardboard.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/cardboard. Accessed 20 Jun. 2026.

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