When I played a music meet a D+9 and a A7/5+. I have tried search in google, but didn't find it. Does anybody know that?
It has two different meanings in the context of chords . Traditionally, the '+' symbol is used to denote an augmented triad, however it is also used to represent a raised interval which is typically represented by a sharp (#).
The first one is most likely an augmented triad with a 9th. The second one just treat the '+' as a sharp where you would play an A7 with a #5.
It's an augmented triad, played by sharpening the fifth by a semitone.
+= sharpened. Sharpened whatever. The number that has + in front of it(or by it) is raised by one semitone so +5 is a sharpened 5th and +9 is a sharpened 9th. The sign means augmented,when used in chord names, and the usual note that's augmented (taken up by a semitone) is the 5th. Thus A = A,C#,E, whereas A+ = A,C#,E#(F). It's common in jazz to alter 5ths and 9ths, so there is also an augmented 9th. Sometimes labelled +9, or aug9.
Note that '+' is different from 'add', even if it has the same connotation in maths.
It means either forget about the fifth and make the fifth sharp instead when it's added after the base chord, or make the note a half step higher when it's added to the chord.
I think the answer is much simpler than all the things everyone is saying as far as popular music charts. What I have seen is that a D+9 chord is a D F# A and an E on top differing from a D9 chord which is a7th chord which is D F# A C E. An A7/5+ is something I have not seen. If they are saying play a 5th in the bass then they are saying add the E in the bass which is the fifth of an A chord. The+ plus may be simply to add the fifth. A + sign to me is just saying add one more note not add all the thirds up to that note.