What is a Chord?

A chord is a combination of three or more notes played together at the same time.  A basic chord has three notes. Complex chords have 4 or 5 different notes; beyond that, larger chords usually use some of the same notes more than once, in multiple octaves (because much more than five different notes in a chord becomes too much for the human brain to hear meaningfully).

Chords are a vital part of music. They are central to nearly every song. Chords are powerful because they make a song happy or sad, and create more complex emotions too. Many songs use just a few basic chords that are repeated as the song plays. Much rock and pop music is based on a repeating flow of just a few chords. Some music uses many chords.  Classical music and jazz often use complex chords. This may be why many people find it easy to listen to rock or pop music but have a harder time with jazz and classical music.

Different types of music are often associated with certain types of chords. For example, children’s music mostly uses basic chords. They are easier to follow and therefore appealing to youngsters. Songs like “Happy Birthday” or “The Wheels of the Bus” use just two or three basic chords.

The word “chord” originated back in the 1500s. Up till then, much of music was based on single notes. As music became more sophisticated, musicians saw that some notes were in “accord” with each other. This meant that certain combinations of notes sounded pleasing when played together. Eventually accord became chord. Chords have now been around for centuries in Western music, but many cultures have never used them much.  If you listen to classical Indian or Chinese music, for example, there are no real chords!

What you should know about chords

  • Chords are combinations of notes played at once.
  • Chords can be simple or complex, or somewhere in between.
  • Chords can be “happy” or “sad,” or raise other emotions. There are chords known as major chords, and ones known as minor chords. Major chords are thought of as happy chords, and the minor ones as sad.
  • Since chords are notes played together, this is easy to do on a guitar, violin, piano, or any instrument that plays more than one note at a time. Instruments that play just one note at a time (such as a flute or a trumpet) can play chords using a technique called “Arpeggio”. This means that the notes of the chord are played in order, one by one. For example, on a flute, three notes of a chord can be played one after the other. This method of playing chords is necessary on wind or brass instruments. This is also known as playing a broken chord.

Chords are a key part of a song. They provide what is known as the “harmony” of the song, which should go together with the melody to express the feelings and movement of the song.  In contrast the “melody” is the part of a song we sing along with or hum to.  The melody implies the harmony--the chords—and for many songs, the melody must be played along with the chords in order to create the right feeling.

Many songs use commonly “chord progressions.” A chord progression is a certain pattern of “chord changes” – the sequence of the different chords played in a song.  There are several very common chord progressions behind most of the music you have ever heard.

For example, a basic progression used in blues and folk music and rock ‘n’ roll is the I-IV-V progressions.  Roman numerals are normally used to describe chord progressions; when it says “I-IV-V” which means 1, 4, and 5, it is referring to the chords based on the first, fourth, and fifth notes in a musical scale.  Every song is written in a certain key—a certain scale. In the key of C, the I, IV, and V chords would be the chords C (I), F (IV), and G (V).  In the key of D, they would be D (I), G(IV), and A(V).


Many songs are written with just a four-chord progression.  Here is a video that shows a young man explaining a four-chord progression and how it is used in songs:

How to play any song with four chords on the piano

By the way, in the video, he uses the I-V-vi-IV progression.  In this notation, the Roman numeral for 6 (vi) is represented with lower case letters. This is because it is a “minor” chord (see section four).

Here is an example of a flute playing chords using the arpeggio method. In the video, watch for the names of the chords as they are being played. The chords are C, F, D minor, and so on – seen in blue type in the sheet music:

Arpeggios in C Maj - Flute lesson - 12l09s00