means The process of shaping metal or other materials by cutting, drilling, grinding, or milling away excess to reach precise dimensions, usually with powered tools.

from From 'machine,' which came into English in the 1500s via French from Latin 'machina' — a device, contrivance, or engine of war — itself borrowed from Greek 'mēkhanē,' meaning a means or expedient, the same root that gives us 'mechanic.' The verb 'to machine' (to work on with a machine) is a much later industrial-age development, and 'machining' as the gerund naming the whole craft of tool-driven metalwork settled into use as factories and lathes multiplied.