PIN n.
lever strikes, to limit its motion. -- Pin drill (Mech.), a drill with a central pin or projection to enter a hole, for enlarging the hole, or for sinking a recess for the head of a bolt, etc.; a counterbore. -- Pin grass. (Bot.) See Alfilaria. -- Pin hole, a small hole made by a pin; hence, any very small aperture…
PINCH n.
A lever having a projection at one end, acting as a fulcrum, -- used chiefly to roll heavy wheels, etc. Called also pinch bar. At a pinch, On a pinch, in an emergency; as, he could on a pinch read a little Latin.
POLAR a.
ite and black in colors; hence, as great an opposition or contrast as possible. -- Polar projection. See under Projection. -- Polar spherical triangle (Spherics), a spherical triangle whose three angular points are poles of the sides of a given triangle. See 4th Pole, 2. -- Polar whale (Zoöl.), the right whale, or b…
POLYCONIC a.
Pertaining to, or based upon, many cones. Polyconic projection (Map Making), a projection of the earth's surface, or any portion thereof, by which each narrow zone is projected upon a conical surface that touches the sphere along this zone, the conical surface being then unrolled. This projection differs from conic pro…