- Informal spelling of thorough.
1946 April 6, “Thoro Overhauling for Manlius Rides”, in Billboard, page 81:
- … the Roller Coaster is to get a thoro overhauling.
1974 January 20, “No Gasoline Rationing Seen”, in Chicago Tribune, Chicago:
- Meanwhile, he said he has ordered a thoro government audit of all major oil company records