Client-server model

A client–server model is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients.

[source: by David Vignoni]

Thin clients

If the clients are thin, meaning that they don't tend to cache their own copy of the data, then there tends to be a lot of client-server communication as data is read or written, and this means data access is subject to network latency, network utilisation is high, and also clients become unavailable when the network partitions or the server fails.

[source: by Peter Astbury]