Lightweight Directory Access Protocol

Lightweight Directory Access Protocol (LDAP ) is an Internet protocol for accessing directory information services that act in accordance with X.500 data and service models." A full description of the protocol can be found in the "Lightweight Directory Access Protocol (LDAP) Technical Specification Road Map" RFC 4510 and its references. Despite its name, LDAP is much more than its protocol (i.e., much more than its HTTP API); it includes specifications of the required operation of systems satisfying its HTTP API and even specifies a standardized model of the data to be used by the HTTP API and managed by the directory service.

Source: Wikipedia — Lightweight Directory Access Protocol (CC BY-SA 4.0)