LDAP stands for Light-weight Directory Access Protocol. It is a network protocol, based on TCP, with optional support for SSL Encryption, that is used to access a hierarchical directory of information on a directory server. LDAP is considered to be lightweight because it is based on a simplified version of X.500 directories.
Directories may contain phone numbers, electronic mail addresses,
Public Key's, computer names and addresses, or any other information
that can be conveniently arranged hierarchically.