CRDT
Also called: Conflict-free replicated data type
A conflict-free replicated data type: a data structure whose copies can be changed independently and always merge to the same result.
Definition
CRDTs include counters (each replica increments its own slot; the value is the sum), sets that handle removals (observed-remove sets), registers and sequences for collaborative text. They let offline devices and multiple regions accept writes without coordination and converge without losing updates, unlike last-write-wins.
In practice
A like counter in two regions: each counts its own likes, and the total is the sum, so no concurrent like is lost.