In the world of client/server architecture, you need to determine if it will be the client or the server that handles the bulk of the workload. By client, we mean the application that runs on a personal computer or workstation and relies on a server to perform some operations.
Thick or thin client architecture is actually quite similar. In both cases, you can consider it as being the client application running on a PC whose function is to send and receive data over the network to the server program. The server would normally communicate that information to the middle-tier software (the backend), which retrieves and stores that information from a database.
While they share similarities, there are many differences between thick and thin clients. Thick and thin are the terms used to refer to the hardware (e.g., how a PC communicates with the server), but the terms are also used to describe applications. While this article deals specifically with hardware issues, be sure to check back as we will continue our Thick and Thin discussion as related to applications.