A suffix is a group of letters added to the end of a word to change its meaning or grammatical function. For example, adding the suffix –ing to the verb run creates the word running, which describes the action in progress. Suffixes can help us form different parts of speech, such as turning nouns into adjectives or verbs into nouns. There are many common suffixes in the English language. For instance, the suffix –ful can be added to the noun beauty to create the adjective beautiful, meaning full of beauty. Understanding suffixes can enhance your vocabulary and help you communicate more effectively.