Green’s Dictionary of Slang

abo n.

also Abo, Abor
[? abbr. of the column ‘Aboriginalities’, launched in the Sydney Bulletin, 15 Oct. 1887 (one regular writer for which signed himself ‘Abo’); AND suggests it was current orally somewhat earlier; the SE Aborigine and Aboriginal are found in 1829 citations; pl. Aborigines is found in 1803]

1. [20C+] (Aus.) an Aboriginal.

2. attrib. use of sense 1.

3. [1910s–30s] (Aus.) an expert on Aborigine and bush customs and folktales.

In compounds

abo’s handbag (n.) (also abo’s briefcase, handbag)

[2000s] (Aus.) any form of boxed (rather than bottled) wine.

In phrases

dark as an abo’s arsehole (adj.)

see under dark adj.