United States: From what I understand, we do not care about age as much as your culture does, but we do care about age a little bit. In my schools, there were some special privileges and some special responsibilities given to people in higher grades. So there was some acknowledgement of that status. (Not a lot. No special names.) but 4th graders look up to 5th graders and sophomores look up to seniors. I wouldn't say that all high schoolers feel equal to each other - but they do not feel extremely unequal either. I would use the phrase "_______ is in a higher grade." Or "_____ is in a different year.*" At work, it doesn't come up as much in my industry - but I would say "______ has been here longer." or "_______ has more seniority." * In high school & college, "year" is the year that you either plan to graduate (if you're still in school) or the year you graduated (once you're done with school.)

Ray's comment is very accurate and well stated. I would add that in union work places you will hear phrases like "he has more seniority than she does" (meaning that he has been working there longer) because the years of service is specifically important in those environments. Also of note, you will hear the junior and senior levels referred to as "upperclassmen" and the lower freshman/sophomore/junior levels referred to as 'underclassmen"

In the US, we have names for the 4 grades in school: Freshman, Sophomore, Junior and Senior. When we say that someone is a senior, we mean that they are in the last year of high school. There are no words that we use to show respect to those who are more senior. We are very informal in high school and all high school students feel equal to one another. At work, most places are informal also. We generally all call each other by first names. The seniority is usually determined by the level of your job and not time with the company. But in this case, we still do not use any special title or way of speaking to the more senior (by job level) people.