Green’s Dictionary of Slang

(Aus./N.Z.) a child’s homemade ‘go-kart’.

1910		Advertiser (Adelaide) 14 Mar. 8/1: A little girl [...] was coasting down a hill on a ‘billy cart’ this afternoon, when she ran into a horse. The animal kicked her on the forehead, and she died soon afterwards.
1915		Colonist (NZ) 123 Sept. 6: Competitions: Decorated barrow: Misses Woolcombe (2) and Morrison; toy barrow, Betty Humphries. Billy-cart : G. Hood.
1917		Grey River Argus (NZ) 28 Aug. 1: A prize of 5s and trophy will be given to the boy or girl with best decorated billy-cart or wheelbarrow in the procession.
1928		Argus (Melbourne) 23 Nov. 6/8: There will be a procession to the school in order to attract people to the opening of the exhibition, and this procession will be of billy-carts.
1930		Canberra Times (ACT) 18 Dec. 2/2: To the average boy who makes a billy cart, [...] the problems involving cubical contents or superficial areas of cylinders present no difficulties.
1959		D. Niland Big Smoke 96: Suddenly a billy-cart screeched at his nerves, and he jerked around to see it, driven by a nine-year-old freak.
1968		A. Buzo Norm and Ahmed (1973) 22: Start off with a billy-cart and finish up with a fleet of Boeing 727s.
1988		McGill Dict. of Kiwi Sl. 15/1: billycart trolley homemade from cannibalised prams and leftover bits of lumber, possibly once associated with carts pulled by billy goats.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 151: [T]he wheels dropped off his billycart when he was halfway down the hill at Ultimo.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].
2010		P. England Knights of Bonalla 142: Billy cart! More like a formula one racing car.