A suffix is a letter or a group of letters that is usually attached to the end of a word to form a new word, as well as alter the way it functions grammatically.
Depending on whether it is a noun, verb, adjective or adverb, a different suffix would be required. For example, the verb read can be altered to become the noun reader by adding the suffix er. The same verb can also be turned into the adjective readable by adding the suffix –able.
It is just as important to understand the definitions of suffixes as prefixes, because they too help us to deduce the meanings of any new words that we learn.