In the case of Boeing, the last 2 numbers are the customer code and it indicates the airline that placed the original order for that particular aircraft. This number does not change and follows the aircraft even after it is sold. Cathay Pacific’s Boeing customer code is 67, so that explains the 777-367 designation. So for example if Cathay Pacific bought a 777-300 from American Airlines, and American had bought that aircraft directly from Boeing…it would be a 777-323 after Cathay acquired it, because that “23” is American’s Boeing customer code.

Regardless of the customer code, it is still referred to in the industry as a 777-300.

Newer Boeing planes like the 777X, 787, 747-8, 737 MAX series do not use the customer code system on their designation. This article may help.

https://en.m.wikipedia.org/wiki/List_of_Boeing_customer_codes

As for Airbus, I believe the number behind the series represents the engine option installed for that aircraft, i’m not 100% sure however.

This comment hit hard, I know that feeling of looking in the mirror and being afraid to open my mouth. I went yesterday for the first time in over 10 years. I felt so much shame and anxiety, I didn’t sleep well for 2 nights leading up to the visit, but boy do I feel better now. Considering it had been so long the news wasn’t as bad as I was expecting, and it was not as painful as i thought it would be (my last visit was not pleasant) Now that i’m over that hump, i’ll be going back much more frequently and will be more diligent with my oral hygene. I wish I had done it sooner. Seriously, for those in a similar situation, just go to the dentist and set things right before it’s too late.