Another post for advanced theory students.
A suspension is a particular type of non-harmony note, or note of melodic decoration. It consists of Preparation, Dissonance (the Suspension itself) and Resolution. This downloadable file explains all about suspensions:
Make sure you understand how each of these suspensions works. You will need to recognise them as notated music, and to write them from figured bass. Suspensions are frequently found in ‘chains’, where the resolution from one suspension is also the preparation for the next. This is a very elegant and lovely way to use suspended dissonances. Here are some examples of suspensions: