turn-infolder

noun
UK /ˈtɜːn ɪnˌfəʊldə/
US /ˈtɜːrn ɪnˌfoʊldər/

A person or thing that folds pages inward.

The turn-infolder made sure every page corner was neatly bent inside.


OTHER MEANINGS

2. A machine that folds paper edges inward during printing.

The turn-infolder jammed when the paper stack was too thick.

3. A tool used in bookbinding to tuck signatures inward.

She reached for the turn-infolder to finish the spine.

4. A software routine that reverses the direction of a fold in a digital document.

The turn-infolder flipped the margin automatically.