A folding knife, fork, and/or spoon combination which can be taken apart into two or three pieces for use. Typically there are studs or extensions of the liner on one part that fit into “slots” in the liner of the other part(s), holding the pieces together for carrying. See: Hobo.
Ka-Bar Hobo with slot knife construction, from the 1938 BSA catalog
Slot Knives, from Smith’s Key, 1816.
Fruit knife with slot knife mechanism, from Smith’s Key, 1816.