Forum: music.stackexchange.com
Tags: <theory><chords><terminology><chord-theory>
Title: Is there a term for chords like F/G and C/D?
Question: Chords like F/G and C/D are really quite common in jazz, blues and soul music yet I have never heard or been able to find a concise name for them.   To be clear, I am referring to any major (or indeed minor) triad with the chord's supertonic in the bass.  I hope someone has heard of a term for these even if it is not an official term.

Answers:
sents: text: These chords are essentially 9sus4 chords.
text: E.g., an F/G has the notes G F A C which are with respect to the root G 1 b7 9 4
text: The only note missing from a complete G9sus4 chord is the fifth (D).
text: Leaving out the fifth does not change the quality or basic sound of the chord.
text: You can get the fifth of the G9sus4 chord if you use Dm7
text: /G instead of
text: F/G. However, the function of these two chords is the same and they are interchangeable.
text: You find both versions frequently in jazz lead sheets.
text: Another frequently used option is to add the major seventh to the top triad, i.e., Fmaj7/G, which would give you a G13sus4 chord.
text: These chords are used extensively in modern jazz and advanced pop music.
text: Read more about this type of chord in this blog post .
text: The vanilla example for the application of this type of chord is the piece Maiden Voyage by Herbie Hancock.
answer_details: author: music.stackexchange.com/users/9724/Matt L.
score: 13
sents: text: In a jazz context, Dom's answer is perfect.
text: However, I also want to say that this chord has become extremely common in pop/rock piano-driven music, for example Elton John, Billy Joel, and Stevie Wonder.
text: And especially in musical theater of this style, for example Jason Robert Brown, Stephen Schwartz, and the "straight to off-off-Broadway" duos like Kerrigan-Lowdermilk and Salzman-Cunningham.
text: In this context, when you have a chord like F/G resolving to C, I think the simplest explanation is that it's primarily an F chord (and thus you have a plagal cadence), with a 5->1 in the bass that strengthens it a bit by adding a bit of dissonance to be resolved, plus outlining an authentic cadence.
text: If you think of it this way, then F/G is really the end of the story.
text: It's an F chord, with a G in the bass.
answer_details: author: music.stackexchange.com/users/10290/MattPutnam
score: 5
sents: text: They are called "Slash chords".
text: Often they exploit the fact that just about ANYTHING can act as a dominant if rooted strongly by the dominant note.
text: You could analyze all the chords here as some flavour of G chord.
text: But slash notation is much more helpful.
text: You could also describe this sort of thing as various chords over a "dominant pedal".
answer_details: author: music.stackexchange.com/users/17003/Laurence Payne
score: 3
sents: text: It does get called an 11th.
text: As in, for example, E,G#,B over an F# bass is F#11.
text: Not an E based chord as expected, but F# (root), E (b7),
text: G# (9), B (4 or 11)
text: A nice example of several of these is David Nichtern's 'Midnight at the Oasis'.
text: Another way to look at it is an 'E add 2' chord.
text: In this case, in first inversion, putting the F# at the bottom.
text: Not a sus 2 which takes the 3 out and puts 2 in instead.
answer_details: author: music.stackexchange.com/users/2808/Tim
score: 2
sents: text: There isn't really a name for these chords, but there is a reason they are used and that may allude to what someone can call them.
text: These chords are way more quartal/quintal in nature.
text: Let's look at the F/G and look at how the notes compare to G as looking from the bass note of each and since the 5th of the bass note is typically implied we'll include the D also.
text: Notice how we get a quartal stack of G - C - F and a quintal stack of G - (D) -
text: A looking at G as the bass.
text: We also can add both together
text: so it looks like the quartal stack of F - C - G - (D) - A or the quintal stack of A
text: - (D)
text: - G - C - F .
text: This shows that the chord is completely quartal or quintal in nature
text: In general quartal and quintal chords don't really have names besides the 6/9 chord which is very quintal in nature.
text: Since the full quartal stack root is also the root note of the chord in the slash chord, I'd call it a second inversion quartal quintad .
text: It's a mouthful, but accurate.
answer_details: author: music.stackexchange.com/users/7222/Dom
score: 2
sents: text: I agree - as a genre they are often called slash chords.
text: Though if you want to instruct someone to play e.g.
text: F/G - you could say play "an F over G".
text: I've heard a few people use this.
answer_details: author: music.stackexchange.com/users/26787/Daviiiide
score: 1

Summary of the answers:
Chords like F/G and C/D are known as Slash chords. Often they exploit the fact that just about ANYTHING can act as a dominant if rooted strongly by the dominant note.  You could also describe this sort of thing as various chords over a "dominant pedal". 
They are called "Slash chords".