Green’s Dictionary of Slang

(Aus.) the anus, the backside.

1952		P. Pinney Road in Wilderness 62: You’re a big bronzed Anzac sitting on your ort drinking free tea .
1962		J. Wynnum Tar Dust 116: Take it from me, there’s more ways of killin’ a cat than fillin’ its ort with sand [AND].
1984		A. Delbridge Aussie Talk 227: Ort n., the anus: In your ort, sport [AND].
1992		D. Hewett Coll. Plays 83: Boysee: Mrs Porter in your ort / Doing all the things you shouldn’t ought.