Old English, "(someone's) deeds, acts, or actions, the things one has done in life," often especially "good deeds, acts of piety, demonstrations of virtue," plural of work, n.. Meaning "operations pertinent to maintaining a large physical place" (private, religious, or municipal) is from late 14c. Meaning "industrial place" (usually with qualifying adjective) is from late 15c. To be in the works in the extended sense of "in the process of being done or made" is by 1973.