Amaj11 is A, C#, E, G#, B and D. Its natural is the same note name as the 4th, while the major 3rd remains.
In a close voicing, sits one fret above . A sharp 11th raises that note one more fret; Amaj11 calls for the natural 11th.
Let both notes sound only when you want that close interval heard. For the sharp 11th instead, played without a 5th, the chord is .
Also written AM11, AΔ11 or A major 11.

Amaj11 in 11th in bass puts D in the bass instead of A, the 11th of the chord. The notes are the same; what changes is what the bass line does, which is most of why you would reach for it — it lets the lowest voice move by step where the root would have jumped.
One of Amaj11’s 9 shapes does this:10-0-9-9-9-9
How you get to it. The turn that lands on Amaj11 is to — the ii and the V of A — and shares its third and seventh with , so the hand barely moves between them.
Hear it land:→→
In which keys. Every note of Amaj11 belongs to F# minor (the ♭III) and A major (the I, the tonic).
Contains Amaj11 and adds thirteenth.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.