pocketknife

• pocket-knife, pocket knife

From pocket +‎ knife.

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).
   • 1878, Mark Twain, Tom Sawyer Abroad; About Magnanimous-Incident Literature:

     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.

   • 1944, Alfred Lief, Camillus: The Story of an American Small Business‎:

     The Army, the Navy, the Maritime Commission, and Lend-Lease demanded more and more pocketknives — for demolition kits, medical kits, aviators’ kits, electricians’ kits; knives with tools, knives with marlin spikes. The pocketknife attained a new status — as indispensable equipment for all men in uniform.

• jack-knife, penknife (synonymous in modern usage)

• Swiss Army knife

• clasp-knife