British post is sorted into two named levels, and this is the upper one. It is the name of the level, so people say a letter went first class, or ask for first class at the counter. The everyday choice is between paying more for speed and paying less and waiting. The same words mean something different in the United States, where first class is simply the ordinary letter class.

This is a judgement about how good something is, and it is a strong one. First-class means at the top of its group, not just fine. It goes before a noun (a first-class meal) or after be (her work is first-class). You can use it for things, and for what a person makes or does. It says nothing about price. In Britain and India people also answer with it on its own, so 'How was the trip?' can get 'First class.' It is not usually compared, so people say absolutely first-class rather than more first-class.

In the American system this is the everyday way to send a letter, not a paid-for upgrade. It is the name of the class, so people say a letter goes first class or is sent by first class. That is worth noticing, because in Britain the same words mean the dearer and faster of two letter classes. So when you meet first class on a form, look first at which country's post system the form belongs to.

This use sits in front of post words: stamp, post, mail, letter, delivery. It points at a level in a postal system, not at quality, so a first-class stamp is not a better-made stamp. The picture of a dearer, faster level matches the British system. In the United States first-class mail is instead the ordinary letter class, so check whose post office is being talked about before you read speed into it.

Here first-class points at a level in a travel system, not at how good something is in general. It sits in front of words like ticket, seat, cabin, lounge, carriage and passenger. The two adjective uses can overlap, because the top class usually is the nicest one, but the test is what follows: travel and hotel words point to the level, while food, work and service usually point to quality.

Travel companies sort their seats into classes, and first class is the top one. It names a real place you can sit in, so you can say the seat is in first class, or that someone travels first class. Below it you may see business class, economy class, second class or standard class, depending on the company. In this use the words are uncountable: say in first class, not in a first class. The words say how good the seat is, not how early the train leaves.

This is the general use that the travel, postal and degree uses all sit inside. Whenever someone draws lines and names the bands, first class is the band at the top. It goes with in (things sit in first class) and with reach or attain (someone works their way up to it). The source records it for ranks as well as goods, including the scouts, where a member attains first class.

British degrees are given out in named classes, and this is the top one. It is countable here, so a student can be awarded a first class. You meet it on results lists, in job adverts and in references. It belongs to the British degree system, so an American transcript usually does not use it.