pocket-knife

Noun

pocketknife (plural pocketknives)

1. A knife small enough for carrying safely and handily in a pocket; usually a folding knife (with blades or tools that the user can fold or retract into the handle).
   • Jimmy had a pocketknife, and he wandered into the drawing-room with it one day, alone, and reduced ten thousand dollars' worth of furniture to an indeterminable value in rather less than three-quarters of an hour.1878, Mark Twain, Tom Sawyer Abroad; About Magnanimous-Incident Literature

   Synonyms:

   jack-knife