guitar chord
C11
Six notes in theory; in practice the third is usually dropped, because the eleventh sits a half step above it.
Every fingering that fits a hand
x33330
moderate · barre · no 5
x33333
moderate · barre · no 3
x30066
easy · no 3
x30360
easy · no 5
x3333x
moderate · barre · no 3, 5
What is true of it
C11 is C, E, G, B♭, D and F — 1, 3, 5, b7, 9 and 11 counted from C.
On an instrument that cannot reach all 6, the 3, 5 and 1 go first, in that order.
The easiest of the 5 fingerings below is x33330: one finger, one of them barring the 3rd fret, held at the 3rd fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
3 of the 5 need a barre.
It leaves out the 5. 6 strings cannot carry 6 notes, and the 5 is the one this chord can lose without changing what it is.
1 string stays silent.
Where its notes are on the neck
The brass dots are C, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
C11/E
010011
C11/G
333330
C11/B♭
630060
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.