n.
a home operated by a social services organization, often to accommodate and support women who are victims of abuse.
Type: 5. Frequency — Transition house may be a Canadian coinage, but its precise origins are unclear. It is possible that the term was initially a proper noun, as one such home was opened in Vancouver in 1973 under the name "Transition House" (see the 1977 quotation). The first widely known women's shelter, however, opened two years earlier in Chiswick, UK, under the name Chiswick Women's Aid. The first home in the US, Rainbow Retreat, was opened in 1973 (Tierney 1982: 207), and in Cambridge, MA, a shelter called "Transition House" was opened in 1975 according to the home's website (see Massachusetts Transition House reference).
Given the data available, the first usage of transition house may have been in reference to the Vancouver shelter referred to above. Note that in the 1977 quotation the term is explained, suggesting that its meaning was not transparent at the time. Transition house is most prevalent in Canada (see Chart 1). Charts 1 and 2 show a clear North American provenance of a term that is North American in principle, possibly Canadian by Origin (Type 1), but certainly Canadian by Frequency (Type 5).
See also COD-2, s.v. "transition house", which is marked "Cdn".
See also: interval house
Images:

Chart 1: Internet Domain Search, 12 Oct. 2012 
Chart 2: Internet Domain Search, 12 Oct. 2012