Green’s Dictionary of Slang

1. (Aus.) a bulldog.

1913		Sport (Adelaide) 7 June 12/1: Kitchen's dogs are Irish bullys, not whippets.
1985		B. Robinson Aussie Bull 54: Two dogs were ‘coupled’ on the footpath and the wife started smashing the ‘bully’ on top with her handbag.

2. (N.Z.) a bulldozer.

2003

McGill Reed Dict. of N.Z. Sl.

3. a bull terrier.

2015

T. Pluck ‘Big Snip’ in Life During Wartime (2018) 10: Their first patient was a gray bully mix named Tuco, a rambunctious boy.