Not a password per se. There are three primary security features:
WEP (Wired Equivalent Privacy)
Wired Equivalent Privacy is intended to stop the interception of radio frequency signals by unauthorized users and is most suitable for small networks. This is so because there is no key management protocol and each key must be entered manually into the clients – this proves to be a very time consuming administrative task. WEP is based on the RC4 encryption algorithm by RSA Data Systems. It works by having all clients and Access Points configured with the same key for encryption and decryption.
SSID (Service Set Identifier)
SSID acts a simple password by allowing a WLAN network to be split up into different networks each having a unique identifier. These identifiers will be programmed into multiple access points. To access any of the networks, a client computer must be configured with a corresponding SSID identifier for that network. If they match then access will be granted to the client computer.
MAC (Media Access Control) address filtering
A list of MAC addresses belonging to the client computers can be inputted into an Access Point and thus only those computers will be allowed access. When a computer makes a request, its MAC address is compared to that of the MAC address list on the Access Point and permission granted or denied. This is a good method of security but only recommended for smaller networks as there is a high rate of work involved in entering each MAC address into every Access Point.
If you enable all three protections your neighbors are essentially out of luck.
