gearing(n = noun.artifact) gear, geartrain, power train, train - wheelwork consisting of a connected set of rotating gears by which force is transmitted or motion or torque is changed; "the fool got his tie caught in the geartrain"
is a kind of wheelwork
is a part of engine
has particulars: epicyclic gear train, epicyclic train, reduction gear
1. Harness. [1913 Webster]
2. The parts by which motion imparted to one portion of an engine or machine is transmitted to another, considered collectively; as, the valve gearing of a locomotive engine; belt gearing; esp., a train of wheels for transmitting and varying motion in machinery. [1913 Webster]
gearing, n.
1 a set or arrangement of gears in a machine.
2 Brit. Commerce a the allocation of part of a dividend to preferred recipients. b the amount of this part.