Q: combination of 5 notes that we have in the 12-note scale. In lots of compositions, chords are more frequently thought of in 4 voices instead of 5 (thank u bach chorales), so we frequently encounter chords that are 4 out of the 5 notes of a dominant 9 chord. Using the G chord, we have G7 = G9 no9, Gadd9 = G9 no7, Dm6 = B hdim7 = G9 no1, and I sometimes also see G9 approximated in 4 voices by leaving out the 5th. These four are all pretty common chords, all quite consonant. But the 5th 4-pitch chord coming from the dom9 that should be just as consonant as the other 4 is G9 no3 = {D,F,G,A} = d minor add4.
A: i'd call it Dmin over G, which is rampantly common, especially in the 1970s 'funk' sort of things. it can be used in the place of G9 or Gmin9. you wouldn't have to specify. james brown songs use these all day. i use them all the time