1. uses based on being female.
(a) [early 19C+] (Aus./N.Z., also meri) an Aboriginal native woman; thus pidgin White Mary, a white woman.
(b) [1900s–10s] (Irish/Aus., also mary ann, mary jane) a female servant.
(c) [1900s–70s] (S.Afr., also coolie Mary) an Indian woman, usu. a fruit or vegetable hawker.
(d) [1940s+] (S.Afr.) any black woman, esp. a domestic servant.
2. (also Marjorie) gay uses.
(a) [1920s+] the most popular camp proper name; typically in phr. get you Mary!
(b) [1950s+] thus, a gay man’s (younger) lover.
(c) [2000s] (S.Afr. gay) a magistrate.
3. drug uses.
(a) [1940s–50s] (US drugs) morphine [the shared initial letter M].
(b) see mary jane n.1
(c) see mary jane n.2
[1980s] (Aus.) to use the lavatory.