In page 13 of Levins’ book, native apps and web apps were mentioned which brings into discussion about thick client and thin client.
Let’s go back to maybe 60s or 70s of Computer Science Department of Indiana University. It was told to me that there was just one computer in the whole department. A big one which is less powerful than your cell phone. So in those days what they would do was they would run wires to the professors’ offices so that all of the professors could use that one computer by just a terminal in their offices (a keyboard and a monitor), a terminal that could not calculate anything and all it could do was sending the data over the wire and then have it back. This was considered as a Thin client because the client does not do anything, it just passes everything on and takes it back. In other words the terminal totally depends on the server to fulfill its computational roles.
Then afterwards when RadioShack, Apple and IBM made personal computers which were a big deal to everyone because you had the whole computer for yourself, you could run applications like Microsoft Word on your PC which is a software that runs right on your desk. These applications (native apps) are considered as Thick client since they are independent of the central server.
Examples of web apps that are thin client: Google, Facebook.
Examples of native apps that are thick client: Adobe Reader, iTunes.