Why are two pitches considered a chord?

Question

According to Wikipedia, a chord is

any harmonic set of two or more notes that is heard as if sounding simultaneously.

But I always thought that two notes aren't a chord, they are an interval. And according to the Intervals Wikipedia page, an interval is

the difference between two pitches.

So my question is this: Can two notes be considered a chord? And why?

Answer 1

An interval is the difference between two pitches regardless of whether they are played together or one at a time.

A chord is a combination of notes played simultaneously.

Just to confuse matters, some sources define a chord as having three or more notes (personally I call two notes a chord).

Answer 2

There is disagreement as to whether we should call two notes a "chord". If we're talking "chord symbol" language, the basic building block is a triad, and with only two notes we can't be sure what triad it is. C and E could be part of C major or of A minor. A chord may be IMPLIED by just two notes though. There's a pretty strong implication of what chords are in the last bar here, even if they aren't completely defined.

Answer 3

The answers given already cover this. I'd just like to point out that whether you call two notes a "chord" or not is another arbitrary convention, like many in the terminology of music (and other subjects, of course). In case of doubt, define your terms first or just name the notes to be played.

Answer 4

The answer to this is not musical per se, it is linguistic.

The word “chord” comes from the word “accord” as in “agreement.” All it takes is two to make an agreement. One is not enough to agree on something, but two or more is.

So if you play two or more notes simultaneously, you have made “an agreement of notes” or “a musical accord” — a “chord.”

Answer 5

An interval is a measurement; a way to analyze music theoretically. A chord is an actual musical component. If you "play intervals", you could technically be said to be playing arpeggios, which are "broken chords".

Many definitions of a chord require a third note, drawing from Euclidean geometric definitions: "two points define a line; three define a plane, four define space". The parallel definitions would state that two notes define movement of pitch, but three are needed for a chord in order to define its quality (major, minor, suspended, augmented, diminished). However, two notes, especially two lines of notes, can indicate the quality of a key in which the performers are singing or playing.

For example, listen to this: There Is No Rose - Traditional Carol

The full choir is in more or less three-part harmony; though there are four parts, two or more double on each sustained chord. But then the middle portion drops to a duet. With the tonal quality of the piece defined by the fuller harmony, the movement of the soloists relative to each other implies the same tonal quality even though the third note, which would explicitly define that quality, isn't there.

Answer 6

Personally, two pitches are not sufficient to define a chord because it is incomplete. Three is the minimum. When you press two strings in a guitar, it may produce some sort of a chord but it is not complete. For instance, when we play a power chord which consists of the root note and the fifth interval, it could be either a major chord or a minor chord. It can only be known based on other chords used along with it.

Answer 7

I'm just going to give my two cents even if it is contrary to the already given answers.

But I always thought that two notes aren't a chord, they are an interval. And according to the Intervals Wikipedia page, an interval is.

These terms are somewhat related. An interval represents the space between two sets of notes either harmonic or melodic. The notes of chords are a set interval from each other (a third.)

The thing is that the main tonal center for the character of a chord is the third. The fifth is a lot less important and only gives any meaningful function when you are busy with augmented or diminished chords.

So in essence, if you have a note and a third you have a rudimentary chord. You also often see in tonal harmony seventh chords that only have three chord notes with the fifth omitted.

It is, in essence, a case of all chords consists of intervals but not all intervals are in chords.

the difference between two pitches.

I would phrase it the distance between two pitches.

...any harmonic set of two or more notes that is heard as if sounding simultaneously.

I don't think this is entirely correct. You have both arpeggios and broken chords that are not played at the same time and to me still count as chords in the broader sense of the word.

Also, piano players often have to roll their chords and if this is the case the notes of the chords are not played exactly at the same time.