In my country, there are several implicit norms that need to be followed by almost every one.


Among all, an important norm is that *juniors does not address their seniors by name*. It happens in both students circle and faculty circle.

Recently, a female assistant professor addressed a male associate professor by his name. It is the first time ever I saw an incident like this personally. I personally considered it as an offense to the male associate professor.

So, I am wondering whether it is a norm in US to address seniors as `sir` or any other respectable salutation instead of addressing by name.