The "arms" that come out from the spindle and attach to the pedals. The "drive side" crank includes the chain rings.
AKA: crankset or crank arms. There are two main types: single piece cranks(1-Pc) and three piece cranks(3-Pc). Single piece cranks are inexpensive and rather heavy. They get the job done on the majority of cheap single speed bikes. Single piece cranks are always made from solid steel and accept only 1/2" pedal spindles. Three piece cranks consist of two crank arms and one spindle. The aluminum or steel arms usually bolt on to the hardened steel spindle for a lighter and stronger crankset than a single piece setup. Three piece cranks accept only 9/16" pedals and are also usually more expensive. The cost difference can be as much as ten times more than single piece.
The two L-shaped metal arms on either side of the bike that run from the pedals to the bottom bracket axle.