Ontario companies must provide an Ontario NUANS to the government with the incorporation documents so that the Ontario government can confirm the name is available and not being used by anyone else.
The Ontario government will allow any name to be registered as long as there is one letter difference to any name registered across Canada at the time of filing.
The Ontario government does not care if you have pre-cleared your name. The onus is on you to ensure your name is not a conflict with any other name. For instance, John's Cement Truck Inc. could be registered even if there is already a registration for John's Cement Truck Ltd. However, you would not want to register that name because it would be a conflict for you down the road. You need to ensure your name is distinct and different from all other names registered not only in Ontario but across Canada.
We can help you ensure your name is clear and has no conflicts.
Resources for Canadian Business Owners pre-clears your proposed name(s) and will ensure the name is available in Ontario and also in any other province or territory in Canada. We will work with you until a name is chosen by you that has no conflicts. We also offer incorporation services if needed.