The chord shape featured in this lesson could be called a few different things. Before we worry too much about what it's called, you first need to hear it! Listen to the sound of the third shape in the below sequence, when played following the first two chords. It sounds massive! We could call it G11, because it contains the 1st, b7th, 9th, and 11th notes of the G Major scale. Note that, if called an "11" this shape does not include the 3rd or 5th, which gives it an ambiguous sound.
The diagrams below could be used as the 1st, 4th, and 5th chords in the key of C Major.
C Major
Many times this "11" chord is referred to in Nashville Number System chord charts as 4/5, meaning that it is the 4th chord in the key with the 5th note in the key in the bass position. In the key of C, this could be written as F/G (F over G) or, more specifically, Fadd9/G. Take a look at the difference in the Fadd9/G construction, versus that of the G11 construction. The same shape, but depending on what we call it, it is constructed differently, based on the root note.
C Major
For context on how to use this chord, let's take a look at this chord progression in another key. This example below is in the key of G Major. Instead of playing D Major as our 5th chord, let's instead use Cadd9/D, which could also be called D11.