From Longman Dictionary of Contemporary Englishpasteboardpaste‧board /ˈpeɪstbɔːd $ -bɔːrd/ noun [uncountable] DBOflat stiff cardboard made by sticking sheets of paper together
Examples from the Corpus
pasteboard• She held the feeling in tight, she squashed it down under the heavy pasteboard covers of the recipe book.• It tasted dry, like pasteboard, but it was food and I couldn't remember the last time I had eaten.• Nowadays boards can means pasteboard, cardboard, strawboard or any other stiff material used in hard-covered books. 