RHYTHM
Rhythm is that pulse you feel when you hear, or think, about music. In Pop music the rhythm is very repetitive.
MELODY
Melody is what is created when you have a collection of notes expressing a developed idea. It’s like a paragraph in a story. A very few notes can be termed a motif. Extending and developing the smaller ideas can become a phrase, then blossom into a full melody.
HARMONY
Harmony is the result of more than one note, or melody, sounding with another.
TIMBRE (pronounced Tam-ber)
Timbre is the sound you hear. The difference between hearing a trumpet play a note and a harp playing the same pitch is the difference in the TIMBRE.
You could name quite a few GENRES of music. Every radio station has a different playlist that represents a select style: Pop, Rock, Jazz, Symphonic, etc. You could invent your own! The list is always changing as musical taste and business marketing grow. But no matter which style you consider it will fall into one of 3 KINDS of music, or a mix of the 3.
The most common KIND of music is called MONOPHONIC. It was the first kind of music that originated and is still the most prevalent type worldwide. It is music that has only one melody. It may have very complicated rhythms and it could be very long and highly developed, but if it has only one melody it remains MONOPHONIC.
During the period of Western history we call the Middle Ages, starting in the Ninth century, people in church heard a second melody while listening to the singing! It wasn’t a developed melody at all, just one note at the beginning! This gradually increased in complexity, especially after the invention of notation around the year 1000 AD.
This 2nd KIND of music is POLYPHONIC, more than one melody at a time. Think of it as horizontal lines, voices. There was no limit on how many voices you could have, or even if the voices had to be in the same language! Think of several Pop songs mashed together, with different lyrics and languages all at once. A jumble of sounds, to be sure, but in the hands of a skilled composer the music would be organized and precise. This kind of music required a more developed listening skill.
The third kind of music was invented at the very beginning of the 17th century. Some of the wisest people in Venice, Italy, began to wonder how to make music as interesting as it is in the POLYPHONIC style, but not as difficult to write, perform, or listen to. They thought that perhaps the harmony created by simultaneous melodies (think horizontal) could be arranged as a progression of chords (think vertical.) A chord is 3 or more notes, together or in sequence. Why not have a melody accompanied by chords? HOMOPHONIC music.
Before this last kind of music was invented chords were the result of separate melodies. So much music is conceived in this last kind in our own time that the ability to hear and appreciate Polyphony has significantly declined. When you listen to any type of music you will be able to identify which of the 3 types you are hearing. Some compositions utilize all three types. Regardless, there are no other kinds of music.