E minor is a minor chord made of 3 notes: E, G, B. It sounds darker and more serious than a major chord, and you hear it in sad songs, ballads and most Bollywood minor-key melodies. It is the i chord of E minor and turns up in 5 other keys.
The library above opens on Em with 14 shapes up and down the neck, starting with hand-checked ones. Tap a shape to hear it, or play it one string at a time.