Definitions for "Bearings"
Keywords:  friction, axle, roller, hub, skate
Bearings have an inner and outer part, which the balls ride on, allowing the wheel to turn.
Why they spin so pretty.
are located on the axle, pedal, and crank. Cup-and-cone ball bearings on the axle can be dis-assembled, tightened, and lubricated. The crank bearing is usually sealed.
Keywords:  handpumps, fulcrum, pivot, lever, pump
("fulcrum") - Pivot points used in all lever action handpumps to connect handles to the pump head.
Directions in three Dimensional space such as 230 on 123--- 230 being the horizontal direction (azimuth) in degrees (0-360) and the second number is the vertical angle or Zenith expressed in 0-360 degrees.