Wireless Access

I'm running a show ap arm state to check the neighbor Ap's

Theres a tab that states Neighbor Density? What exactly does this Tab mean?

From the ArubaOS Command Reference Guide, page 603:

Neighbor Density The neighborhood density for the specified AP is listed with the values A/B/C/D,
where:
A= Number of the AP’s clients heard in the AP neighbor’s client list
B= Number of clients in AP neighbor’s client list
C= Density percentage, (AP clients heard in in the AP neighbor client list / AP client density * 100).
D= Density Percentage (AP clients heard in the AP neighbor’s client list /neighbor client density * 100)