Sus chords are made up of the 1st, 4th, and 5th notes of the major scale. Sus chords can be referred to as "sus4" or just "sus."
"Sus" is short for suspended. A suspension is a note that wants to resolve downward.
Below are a few sus chords that use open strings, study them and be sure to take the quiz to lock in the knowledge.
Esus
Common open Esus shape