What does "working" mean?

Working: -- Working class, the class of people who are engaged in manual labor, or are dependent upon it for support; laborers; operatives; -- chiefly used in the plural. -- Working day. See under Day, n. -- Working drawing, a drawing, as of the whole or part of a structure, machine, etc., made to a scale, and intended to be followed by the workmen. Working drawings are either general or detail drawings. -- Working house, a house where work is performed; a workhouse. -- Working point (Mach.), that part of a machine at which the effect required; the point where the useful work is done.