Green’s Dictionary of Slang

(Aus.) a large suitcase, a school satchel.

1900		Bulletin (Sydney) 14 Apr. 32/2: I went upstairs slowly; I wuz sparrin’ fer time. I dumped me port across the floor and pretended ter rummage fer the fiver.
1905		Sun. Times (Perth) 23 July 4/8: Jim went and opened up his ‘port’ — his port was just a bag.
1946		D. Stivens Courtship of Uncle Henry 53: You take your port up and come back to the car.
1982		N. Keesing Lily on the Dustbin 107: Every fibre suitcase (or ‘port’ in Queensland and a few other places).
1993		Aus. Word Map 🌐 school port. a child’s case used for school: He put his schoolbooks into his port.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers xxi: The minute he’d shifted his big port and his overcoat into Sadie Greene’s, The Flea went down to the paper shop .
2001		OnLine Dict. of Playground Sl. 🌐 port n. school satchel.
2017		T. Spicer Good Girl Stripped Bare 12: After strapping my port on my back, I peddle along with a song in my heart.