(Australian) a ship carrying (assisted) immigrants to Australia; (also, chiefly North American) a ship or boat carrying immigrants (especially illegal ones) to the United States or Canada.
Origin
1940s.
Definition of migrant ship in US English:
migrant ship
noun
(Australian) a ship carrying (assisted) immigrants to Australia; (also, chiefly North American) a ship or boat carrying immigrants (especially illegal ones) to the United States or Canada.