We don't have synonyms for rosco yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are rosso, fosco and ronco.
(n) :
(rail transport, UK) Abbreviation of rolling stock (leasing) company. [(rail transport, uncountable, collectively) All vehicles that move on a railway, powered or unpowered.]
(n) :
(rail transport, UK) Abbreviation of rolling stock (leasing) company. [(rail transport, uncountable, collectively) All vehicles that move on a railway, powered or unpowered.]