1963  Mr. Sullivan . . . yelled down to . . . [the] owner of the two-storey frame duplex...
2n. one of the dwellings of such a building.
1959  Emile Groulx, 68, living in the upstairs duplex, also smelled smoke. . .
3n.Lumbering See 1942 quote.
1942  A yarder may be a single-purpose donkey or it may be a "duplex " machine, having loading drums as well as mainline and haulback drums fed their steam from the same boiler.
1960  Most old-time loggers will remember Bloedel, Stewart and Welch's big logging camp . . . near Powell River. This camp started operations also in 1911 and the superintendent's name was Reilly, who . . . invented the steam duplex system of loading and used railways to a larger extent than ever before used in the woods.
1963  There's where you hear the duplex shrill / As it roars, screams and whines. . . .