1 n. — Housing
a building providing basic communal sleeping quarters for workers.
Type: 2. Preservation — Bunkhouses were often provided for workers in remote areas, for example, railway workers, miners and loggers. The term also refers to dormitories at summer camps and resorts. Bunkhouse is most likely a preservation from British English, brought over by the early settlers to North America. The origin of the term is unknown; however, the OED dates the term back to 1877. In Canada, the term is found in each province, with a little more currency in New Brunswick and British Columbia (see Chart 1).
See also Gage-1, s.v. "bunkhouse", ITP Nelson, s.v. "bunkhouse".
2 n. — Housing, Outdoors
a separate building with sleeping quarters for guests at a summer house, camp or resort.
This meaning is equivalent to bunkie, which is an Ontario term.
See also COD-2 s.v. "bunkhouse", which is marked "Cdn = BUNKIE".
See also: bunkie
Images:

Image 1: Bunkhouse. Source: Wikimedia Commons. Photo: D. Robertson 
Chart 1: Regional Domain Search, 17 Nov. 2013