The term 'mechanical' is derived from the Latin word machina. The Oxford English Dictionary defines the adjective mechanical as the nature of a machine or machines, and relating to or caused by movement, physical forces, properties or agents. Similarly Merriam-Webster Dictionary defines 'mechanical' as relating to machinery or tools.
Mechanical machines employ power to achieve desired forces and movement. The mechanism of a mechanical system is assembled from components called machine elements. These elements provide structure for the system and control its movement. A mechanical system manages power to accomplish a task that involves forces and movement.
Mechanical
logic gates can be build with metallic plates and rods. A
punched tape is a mechanical way to store
bits.
The
Z1 of
Konrad Zuse was a mechanical machine and its engine was the only current-carrying part. In contrast the
Z2 used both mechanical and
electromechanical means for different functional units. The
Helix-Tower is a mechanical construction.
Supplement: A mechanical system consists of
(i) a power source and actuators that generate forces and movement,
(ii) a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement, and
(iii) a controller with sensors that compares the output to a performance goal and then directs the actuator input.
This can be seen in Watt's steam engine in which the power is provided by steam expanding to drive the piston. The walking beam, coupler and crank transform the linear movement of the piston into rotation of the output pulley. Finally, the pulley rotation drives the flyball governor which controls the valve for the steam input to the piston cylinder.
cf.
Wikipedia and
Wikipedia