You can learn more about AP classes via the Collegeboard website, here: AP Programs

Essentially, AP classes are higher level classes which students can take to get college-level study in a variety of topics. I believe there are over 30 different subjects covered, from Statistics to Spanish.

At the end of the year, all AP students have the option of taking a final AP exam to gauge your competency in the subject area. Exams are scored on a scale of 1-5 (1 being the worst, 3 being average, 4 being above average, and 5 being perfect). The more 5s, the better.

On top of all that, your performance on these exams can lead to college credit. My friend who goes to UGA was able to start his freshmen year with a sophomore-level standing due to his AP credit.

If you take these classes, make sure to register for all the corresponding exams. Doing well can mean college credit along with AP Scholar distinction, which means you're one of the very best students in your school, state, or nation.

My school offered both AP and IB. This may be a slightly different issue, but if your school offers IB as well, I'm sure you'll be asking this question soon enough. Which is better: AP or IB? In my opinion, it's IB because you get international standing and course curriculum is much harder. I think any top-tier school knows and understands that IB classes hold more rep than AP classes.

Advanced Placement

AP classes is Advanced Placement classes. All it means is that you take higher classes because your good in that certain subject. Such as AP english. Taking a higher class for english.

AP classes allow you to get credit for college level courses if you pass the AP test for the class at the end of the year. This can save you money when you actually enter college.