A7

A Dominant 7th · 4 fingerings
The dominant seventh adds a flat seventh to the major triad, and that interval against the major third is what creates its restless, bluesy pull. A7 is the engine of blues, where whole progressions are built from dominant chords, and it's the classic V chord that drives a resolution home in jazz and pop alike.
23
A7 · position 1
12
A7 · position 2
5fr132
A7 · position 3 · fret 5
7fr1324
A7 · position 4 · fret 7

Practice this Chord

Play-alongs whose transcribed chord changes include A7.