The terms “Certified Translator”, “Certified Court Interpreter”, “Certified Conference Interpreter” and “Certified Terminologist” each have title protection granted by the Provincial Government to the Society of Translators and Interpreters of BC (STIBC), a self-regulating professional society.
This means that it is un-lawful for any translator (for example) to present himself as a “Certified Translator” unless he is a member in good standing of STIBC and is certified by STIBC in the relevant language combination.
The situation is similar in Ontario and New Brunswick. Quebec has a provincial government body that regulates the profession.
However, many people consider themselves to be “Certified”. In particular – people who have been examined by Canada Immigration may well be entitled to call themselves “certified interpreters” inside the Immigration Department or a refugee hearing room but are not Certified Court Interpreters.
Similarly, a person who may have been dubbed “certified interpreter” “or even certified court interpreter” by a school or agency may not present himself as a Certified Court Interpreter.
If you have any doubt about an interpreter’s use of the term “certified”, a) something is probably amiss and b) you should check on the STIBC website.