A theorem describing the limitations of sharing stateful data across a network. CAP stands for Consistency, Availability, Partition Tolerance. Consistency means that data requested from two parts of the network has the same value at the same time. Availability means that data can be requested and retrieved immediately from any part of the network. Partition Tolerance means that gaps in network connectivity do not break Consistency or Availability. Consistency and Availability are both possible while the network has no Partitions but real world networks are frequently partitioned. (see Eventual Consistency and PACELC theorem).