This feedback is specifically for Expedia.ca. Air Canada online check-in asks for booking reference #. There's no such term in Expedia documents. I now know it is the "confirmation code" in Expedia from trial and error. In addition, the confirmation code in the confirmation email differs from the one in Expedia account. The combination of the above 2 discrepancies made my online check-in a 30-minute ordeal. When I called Expedia to provide this feedback, the agent implicitly refused to take and forward the feedback. Instead, she said if the aircraft or flight changes, the confirmation code will also change. So I have to always login to my Expedia account to get the most updated confirmation number. However, the aircraft and the flight haven't changed since the confirmation email. I learned from this painful experience to always login to Expedia for the correct code. But my feedback is still valid. Expedia should use consistent terms/language, and provide consistent information like confirmatiom code.