distributed hash table

Definition

It is a distributed system that provides a lookup service similar to a hash table: key-value pairs are stored in a DHT, and any participating node can efficiently retrieve the value associated with a given key. The main advantage of a DHT is that nodes can be added or removed with minimum work around re-distributing keys.

More detail

Keys are unique identifiers which map to particular values, which in turn can be anything from addresses, to documents, to arbitrary data.
(Source: Wikipedia)