JJust as music isn't just music nowadays (it's pop, dance, hip-hop, etc.), classical music wasn't - and isn't - just classical music. The great composers had guidelines to follow and many even revolutionized a few of the standards.
- Symphony. A symphony is the mother of all classical musical pieces. It is typically at least half an hour long, composed of four movements, and to play it, a full-body orchestra has to be involved. As you can imagine, a symphony is very hard create and all the great composers wrote at least a couple of symphonies to prove their greatness.
- Sonata. Sonatas, like symphonies, can be just as long to play and contain just as many movements, but they are generally played by only one or a few players.
- Sonatina. A sonatina is a baby sonata. It is still played by only one or a few players, but the length of the music is not as long, and there are noticeably fewer movements.
- Concerto. A concerto is basically a song written for a solo player, but the soloist plays it with an orchestra backing him/her up. When played during a concert, the soloist stands or sits in front of the rest of the orchestra on the stage. Oftentimes, classical concert-goers go to performances mainly to hear the concerto.
- Dance. Some classical music is meant to be danced to. Waltzes fall under this category. You can tell if a piece is a dance if it's repetitive and has a steady rhythm that you find yourself moving to. (Another dead giveaway is the word "dance" or "waltz" in the title.)
- Serenade. Serenades were basically created to be background music. Kings and other important people used to order for them to be played during dinner parties and other functions where it was good to have music involved but not to the point where they were the focus of the gathering. Most serenades last for about half an hour and are generally uncomplicated, mild, and soothing to listen to.
- Theme and Variation. A musical theme is a melody that's introduced at the beginning of a piece and repeated over and over again throughout the rest of the song with slight variations. It's quite simple, really, because only one tune is really involved, but it sounds great. Pachelbel's Canon in D is a wonderful example of a theme and its variations.
- Rhapsody. Rhapsodies (and fantasias, the sisters of rhapsodies) have no form, so when you have no idea what category of classical music a song falls under, chalk it up as a rhapsody. This is not to say that these types of music were complete ramblings of notes - think of Queen's Bohemian Rhapsody, a song that's wacky and meandering, but you can still sing and violently bob your head along with it because it has a distinct tune and rhythm.
- Tone Poem. Tone poems are similar to rhapsodies in that they have no specified structure. But their specialty is to tell a story. A great example of a tone poem is Sergei Prokofiev'sPeter and the Wolf. Or, for a more modern example, John William's Star Wars score.
- Overture. Only a couple of minutes long, overtures (also known as preludes) were written to evoke a certain mood or emotion like tragic sadness or triumphant happiness. Nowadays, overtures are composed to be played before the curtain goes up at a Broadway show or opera.
- Ballet. Some classical music was composed for the explicit reason of accompanying the ballet. In the beginning, ballet music was written to be background music so it wasn't very striking. But then Peter Tchaikovsky came along and revolutionized the genre with his stunning pieces and people started to listen to just the music without watching the dancing.
