Wiktionary
folding knife
n. A class of knives in which the blade or multiple blades can be folded inside the handle.
Usage examples of "folding knife".
He removed a bone-handled folding knife from the pocket of his uniform raincoat and opened the blade.
He took the folding knife from his pocket and slashed the top off of the jug.
I had a Spyderco folding knife clipped over the underwire of my bra.
Yount took out a formidable folding knife and opened from it a small corkscrew.
He considered the folding knife for a moment and then handed it back without expression.