folding rule (noun) ruler: tool for measuring or calculating length
Sinonime: 9 mm., Saturday-night special, Uzi, blaster, cannon,
difference*, equalizer, flintlock, forty-five, handgun, hardware, howitzer, magnum, mortar, musket, ordnance, peashooter, persuader,
piece*, pistol, revolver, rifle, rod, shotgun, thirty-eight